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readtable

Create table from file

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Syntax

T = readtable(filename)
T = readtable(filename,Name,Value)
T = readtable(filename,opts)
T = readtable(filename,opts,Name,Value)

Description

example

T = readtable(filename) creates a table by reading column-oriented data from a text file, spreadsheet (including Microsoft® Excel®) file, XML file, HTML file, or a Microsoft Word document. readtable detects elements of your data, such as delimiter and data types, to determine how to import your data.

example

T = readtable(filename,Name,Value) specifies options using one or more name-value arguments. For example, you can read the first row of the file as variable names or as data by using the ReadVariableNames name-value argument.

example

T = readtable(filename,opts) creates a table using the options specified by the import options object opts. Use an import options object to configure how readtable interprets your file. Compared to name-value arguments, an import options object provides more control, better performance, and reusability of the file import configuration.

example

T = readtable(filename,opts,Name,Value) creates a table using both an import options object and name-value arguments. If you specify name-value arguments in addition to an import options object, then readtable supports only the ReadVariableNames, ReadRowNames, DateLocale, and Encoding name-value arguments for text files, and the ReadVariableNames, ReadRowNames, Sheet, and UseExcel name-value arguments for spreadsheet files.

Examples

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Open Live Script

Import the contents of a text file into a table. The resulting table contains one variable for each column in the file and uses the entries in the first line of the file as variable names.

File contents of myCsvTable.dat

T = readtable("myCsvTable.dat")
T=5×6 table
      LastName      Gender    Age    Height    Weight    Smoker
    ____________    ______    ___    ______    ______    ______

    {'Smith'   }    {'M'}     38       71       176        1   
    {'Johnson' }    {'M'}     43       69       163        0   
    {'Williams'}    {'F'}     38       64       131        0   
    {'Jones'   }    {'F'}     40       67       133        0   
    {'Brown'   }    {'F'}     49       64       119        0
Open Live Script

Create a table from a text file that contains data gaps. By default, readtable fills the gaps with the appropriate missing values. 

T = readtable("headersAndMissing.txt")
T=5×6 table
     LastName        Gender      Age    Height    Weight    Smoker
    ___________    __________    ___    ______    ______    ______

    {'Wu'     }    {'M'     }     38      71       176        1   
    {'Johnson'}    {'M'     }     43      69       163        0   
    {'Sanchez'}    {'F'     }     38      64       131        0   
    {'Brown'  }    {'F'     }    NaN      67       133        0   
    {'Picard' }    {0x0 char}    NaN      64       119        0

To omit the rows with the data gaps, specify the MissingRule name-value argument.

T = readtable("headersAndMissing.txt",MissingRule="omitrow")
T=3×6 table
     LastName      Gender    Age    Height    Weight    Smoker
    ___________    ______    ___    ______    ______    ______

    {'Wu'     }    {'M'}     38       71       176        1   
    {'Johnson'}    {'M'}     43       69       163        0   
    {'Sanchez'}    {'F'}     38       64       131        0
Open Live Script

Configure how readtable interprets your file using an import options object. For example, use an import options object to read only a subset of a text file.

First, create an import options object by using detectImportOptions to detect aspects of your text file, including variable names and types, delimiters, and white-space characters. In this case, detectImportOptions creates a DelimitedTextImportOptions object.

opts = detectImportOptions("airlinesmall.csv")
opts = 
  DelimitedTextImportOptions with properties:

   Format Properties:
                    Delimiter: {','}
                   Whitespace: '\b\t '
                   LineEnding: {'\n'  '\r'  '\r\n'}
                 CommentStyle: {}
    ConsecutiveDelimitersRule: 'split'
        LeadingDelimitersRule: 'keep'
       TrailingDelimitersRule: 'ignore'
                EmptyLineRule: 'skip'
                     Encoding: 'ISO-8859-1'

   Replacement Properties:
                  MissingRule: 'fill'
              ImportErrorRule: 'fill'
             ExtraColumnsRule: 'addvars'

   Variable Import Properties: Set types by name using setvartype
                VariableNames: {'Year', 'Month', 'DayofMonth' ... and 26 more}
                VariableTypes: {'double', 'double', 'double' ... and 26 more}
        SelectedVariableNames: {'Year', 'Month', 'DayofMonth' ... and 26 more}
              VariableOptions: [1-by-29 matlab.io.VariableImportOptions] 
	Access VariableOptions sub-properties using setvaropts/getvaropts
           VariableNamingRule: 'modify'

   Location Properties:
                    DataLines: [2 Inf]
            VariableNamesLine: 1
               RowNamesColumn: 0
            VariableUnitsLine: 0
     VariableDescriptionsLine: 0 
	To display a preview of the table, use preview

Specify the subset of variables to import by modifying the import options object. Then, import the subset of data using readtable with the import options object.

opts.SelectedVariableNames = ["TaxiIn","TaxiOut"];
T = readtable("airlinesmall.csv",opts);
Open Live Script

Create a table from a spreadsheet that contains variable names in the first row and row names in the first column. Display the first five rows and first four variables of the table.

T = readtable("patients.xls",ReadRowNames=true);
T(1:5,1:4)
ans=5×4 table
                  Gender      Age              Location               Height
                __________    ___    _____________________________    ______

    Smith       {'Male'  }    38     {'County General Hospital'  }      71  
    Johnson     {'Male'  }    43     {'VA Hospital'              }      69  
    Williams    {'Female'}    38     {'St. Mary's Medical Center'}      64  
    Jones       {'Female'}    40     {'VA Hospital'              }      67  
    Brown       {'Female'}    49     {'County General Hospital'  }      64
Open Live Script

Create a table using data from a specified region of a spreadsheet. Use the data from the 5-by-3 rectangular region between the corners C2 and E6. Do not use the first row of this region as variable names. The resulting table uses the default variable names instead.

T = readtable("patients.xls",Range="C2:E6",ReadVariableNames=false)
T=5×3 table
    Var1                Var2                 Var3
    ____    _____________________________    ____

     38     {'County General Hospital'  }     71 
     43     {'VA Hospital'              }     69 
     38     {'St. Mary's Medical Center'}     64 
     40     {'VA Hospital'              }     67 
     49     {'County General Hospital'  }     64
Open Live Script

Configure how readtable interprets your file using an import options object. For example, use an import options object to read only specified variables from a spreadsheet file.

First, create an import options object from a file by using detectImportOptions to detect aspects of your spreadsheet file, including variable names and types. In this case, detectImportOptions creates a SpreadsheetImportOptions object.

opts = detectImportOptions("patients.xls")
opts = 
  SpreadsheetImportOptions with properties:

   Sheet Properties:
                        Sheet: ''

   Replacement Properties:
                  MissingRule: 'fill'
              ImportErrorRule: 'fill'

   Variable Import Properties: Set types by name using setvartype
                VariableNames: {'LastName', 'Gender', 'Age' ... and 7 more}
                VariableTypes: {'char', 'char', 'double' ... and 7 more}
        SelectedVariableNames: {'LastName', 'Gender', 'Age' ... and 7 more}
              VariableOptions: [1-by-10 matlab.io.VariableImportOptions] 
	Access VariableOptions sub-properties using setvaropts/getvaropts
           VariableNamingRule: 'modify'

   Range Properties:
                    DataRange: 'A2' (Start Cell)
           VariableNamesRange: 'A1'
                RowNamesRange: ''
           VariableUnitsRange: ''
    VariableDescriptionsRange: '' 
	To display a preview of the table, use preview

Specify which variables to import by modifying the import options object. Then, import the specified variables using readtable with the import options object. Display the first 5 rows of the table.

opts.SelectedVariableNames = ["Systolic","Diastolic"];
T = readtable("patients.xls",opts);
T(1:5,:)
ans=5×2 table
    Systolic    Diastolic
    ________    _________

      124          93    
      109          77    
      125          83    
      117          75    
      122          80
Open Live Script

Import the contents of an XML file into a table.

The students.xml file has seven sibling nodes named Student, which each contain the same child nodes and attributes. 

type students.xml
<?xml version="1.0" encoding="utf-8"?>
<Students>
    <Student ID="S11305">
        <Name FirstName="Priya" LastName="Thompson" />
        <Age>18</Age>
        <Year>Freshman</Year>
        <Address>
            <Street xmlns="">591 Spring Lane</Street>
            <City>Natick</City>
            <State>MA</State>
      </Address>
      <Major>Computer Science</Major>
      <Minor>English Literature</Minor>
   </Student>
   <Student ID="S23451">
        <Name FirstName="Conor" LastName="Cole" />
        <Age>18</Age>
        <Year>Freshman</Year>
        <Address>
            <Street xmlns="">4641 Pearl Street</Street>
            <City>San Francisco</City>
            <State>CA</State>
        </Address>
        <Major>Microbiology</Major>
        <Minor>Public Health</Minor>
    </Student>
    <Student ID="S119323">
        <Name FirstName="Morgan" LastName="Yang" />
        <Age>21</Age>
        <Year>Senior</Year>
        <Address>
            <Street xmlns="">30 Highland Road</Street>
            <City>Detriot</City>
            <State>MI</State>
        </Address>
        <Major>Political Science</Major>
   </Student>
   <Student ID="S201351">
        <Name FirstName="Salim" LastName="Copeland" />
        <Age>19</Age>
        <Year>Sophomore</Year>
        <Address>
            <Street xmlns="">3388 Moore Avenue</Street>
            <City>Fort Worth</City>
            <State>TX</State>
        </Address>
        <Major>Business</Major>
        <Minor>Japanese Language</Minor>
   </Student>
   <Student ID="S201351">
        <Name FirstName="Salim" LastName="Copeland" />
        <Age>20</Age>
        <Year>Sophomore</Year>
        <Address>
            <Street xmlns="">3388 Moore Avenue</Street>
            <City>Fort Worth</City>
            <State>TX</State>
        </Address>
        <Major>Business</Major>
        <Minor>Japanese Language</Minor>
    </Student>
    <Student ID="54600">
        <Name FirstName="Dania" LastName="Burt" />
        <Age>22</Age>
        <Year>Senior</Year>
        <Address>
            <Street xmlns="">22 Angie Drive</Street>
            <City>Los Angeles</City>
            <State>CA</State>
        </Address>
        <Major>Mechanical Engineering</Major>
        <Minor>Architecture</Minor>
   </Student>
    <Student ID="453197">
        <Name FirstName="Rikki" LastName="Gunn" />
        <Age>21</Age>
        <Year>Junior</Year>
        <Address>
            <Street xmlns="">65 Decatur Lane</Street>
            <City>Trenton</City>
            <State>ME</State>
        </Address>
        <Major>Economics</Major>
        <Minor>Art History</Minor>
   </Student>
</Students>

First, create an XMLImportOptions object by using detectImportOptions to detect aspects of your XML file. Read just the street names into a table by specifying the VariableSelectors name-value argument as the XPath expression of the Street element node. Register a custom namespace prefix to the existing namespace URL by setting the RegisteredNamespaces name-value argument.

opts = detectImportOptions("students.xml",RegisteredNamespaces=["myPrefix",""], ...
    VariableSelectors="//myPrefix:Street");

Then, import the specified variable using readtable with the import options object. 

T = readtable("students.xml",opts)
T=7×1 table
          Street       
    ___________________

    "591 Spring Lane"  
    "4641 Pearl Street"
    "30 Highland Road" 
    "3388 Moore Avenue"
    "3388 Moore Avenue"
    "22 Angie Drive"   
    "65 Decatur Lane"
Open Live Script

Import a table from a Microsoft Word document into a table in MATLAB. In this case, the document contains two tables, and the second table contains merged cells. Read the second table by setting the TableIndex name-value argument. Skip rows that have cells with merged columns by setting the MergedCellColumnRule name-value argument. 

filename = "MaintenanceReport.docx";
T = readtable(filename,TableIndex=2,MergedCellColumnRule="omitrow")
T=3×5 table
                                 Description                                       Category          Urgency         Resolution          Cost  
    _____________________________________________________________________    ____________________    ________    __________________    ________

    "Items are occasionally getting stuck in the scanner spools."            "Mechanical Failure"    "Medium"    "Readjust Machine"    "$45"   
    "Loud rattling and banging sounds are coming from assembler pistons."    "Mechanical Failure"    "Medium"    "Readjust Machine"    "$35"   
    "There are cuts to the power when starting the plant."                   "Electronic Failure"    "High"      "Full Replacement"    "$16200"

Alternatively, you can select a table with an XPath selector by using the TableSelector name-value argument. To select the Microsoft Word document table that contains the text "Description", use the XPath selector "//w:tbl[contains(.,'Description')]". 

T = readtable(filename, ...
    TableSelector="//w:tbl[contains(.,'Description')]", ...
    MergedCellColumnRule="omitrow")
T=3×5 table
                                 Description                                       Category          Urgency         Resolution          Cost  
    _____________________________________________________________________    ____________________    ________    __________________    ________

    "Items are occasionally getting stuck in the scanner spools."            "Mechanical Failure"    "Medium"    "Readjust Machine"    "$45"   
    "Loud rattling and banging sounds are coming from assembler pistons."    "Mechanical Failure"    "Medium"    "Readjust Machine"    "$35"   
    "There are cuts to the power when starting the plant."                   "Electronic Failure"    "High"      "Full Replacement"    "$16200"
Open Live Script

Import the first table from the URL /help/matlab/text-files.html that contains the text "readtable" using the XPath selector "//TABLE[contains(.,'readtable')]". The table does not have a header row, so set the ReadVariableNames name-value argument to false.

url = "/help/matlab/text-files.html";
T = readtable(url,TableSelector="//TABLE[contains(.,'readtable')]", ...
    ReadVariableNames=false)
T=4×2 table
          Var1                      Var2            
    ________________    ____________________________

    "readtable"         "Create table from file"    
    "writetable"        "Write table to file"       
    "readtimetable"     "Create timetable from file"
    "writetimetable"    "Write timetable to file"

Input Arguments

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Name of the file to read, specified as a string scalar or character vector. readtable supports reading data from text, spreadsheet, XML, and HTML files as well as Microsoft Word documents.

If filename does not include an extension, use the FileType name-value argument to indicate the file format. By default, readtable creates variables that have data types that are appropriate for the data values detected in each column of the input file.

Depending on the location of your file, filename can take on one of these forms.

Location

Form

Current folder or folder on the MATLAB® path

Specify the name of the file in filename.

Example: "myFile.txt"

File in a folder

If the file is not in the current folder or in a folder on the MATLAB path, then specify the full or relative pathname in filename.

Example: "C:\myFolder\myFile.xlsx"

Example: "dataDir\myFile.txt"

Internet URL

If the file is specified as an internet uniform resource locator (URL), then filename must contain the protocol type "http://" or "https://".

Example: "http://hostname/path_to_file/my_data.csv"

Remote Location

If the file is stored at a remote location, then filename must contain the full path of the file specified with the form:

scheme_name://path_to_file/my_file.ext

Based on the remote location, scheme_name can be one of the values in this table.

Remote Locationscheme_name
Amazon S3™s3
Windows Azure® Blob Storagewasb, wasbs
HDFS™hdfs

For more information, see Work with Remote Data.

Example: "s3://bucketname/path_to_file/my_file.csv"

Example: "wasbs://path_to_file/my_file.csv"

Example: "hdfs:///path_to_file/my_file.csv"

Text Files

  • Files with .txt, .dat, or .csv extensions are read as delimited text files.

  • By default, readtable creates one table variable for each column in the file and reads variable names from the first row of the file. Empty fields are converted to either NaN for a numeric variable or an empty character vector for a text variable. White space is ignored when reading the file.

  • All lines in the text file must have the same number of delimiters.

For more options, see the name value arguments for Text Files.

For commonly used text file workflows, see Import Data from Text File to Table.

Spreadsheet Files

  • Files with .xls, .xlsb, .xlsm, .xlsx, .xltm, .xltx, or .ods extensions are read as spreadsheet files.

  • By default, readtable creates one table variable for each column in the file and reads variable names from the first row of the file.

  • On Windows® systems with Microsoft Excel software, readtable reads any Excel spreadsheet file format recognized by your version of Excel. If your system does not have Microsoft Excel for Windows or if you are using MATLAB Online™, then readtable operates with the UseExcel property set to false and reads only files with .xls, .xlsm, .xlsx, .xltm, and .xltx extensions.

For more options, see the name value arguments for Spreadsheet Files.

For commonly used spreadsheet file workflows, see Read Spreadsheet Data into Table.

XML Files

  • Files with the .xml extension are read as Extensible Markup Language (XML) files.

  • By default, readtable creates one table variable for each element or attribute node detected as a table variable. Variable names correspond to element and attribute names.

  • Large files in XLSX format sometimes load slowly. For better import and export performance, Microsoft recommends that you use the XLSB format.

For more options, see the name value arguments for XML Files.

Microsoft Word Document Files

  • Files with the .docx extension are read as Microsoft Word document files.

  • By default, readtable imports data from the first table in the document, creates one table variable for each column in the file, and reads variable names from the first row of the table.

For more options, see the name value arguments for Microsoft Word Document Files.

HTML Files

  • Files with the .html, .xhtml, or .htm extensions are read as Hypertext Markup Language (HTML) files.

  • By default, readtable imports data from the first <TABLE> element, creates one table variable for each column in the file, and reads variable names from the first row of the table.

For more options, see the name value arguments for HTML Files.

File import options, specified as one of the import options objects in the table, created by either the detectImportOptions function or the associated import options function. The import options object contains properties that configure the data import process. readtable uses only the relevant properties of each import options object.

File TypeImport Options Object
Text filesDelimitedTextImportOptions object
Fixed-width text filesFixedWidthImportOptions object
Spreadsheet filesSpreadsheetImportOptions object
XML filesXMLImportOptions object
Microsoft Word documentWordDocumentImportOptions object
HTML filesHTMLImportOptions object

For more information on how to control your import, see Control How MATLAB Imports Your Data.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: readtable(filename,ReadVariableNames=false) indicates that the first row of the file does not correspond to variable names.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: readtable(filename,"ReadVariableNames",false) indicates that the first row of the file does not correspond to variable names.

Text Files

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Type of file, specified as one of these values.

ValueFile Type
"spreadsheet"Spreadsheet files
"text"Text files
"delimitedtext"Delimited text files
"fixedwidth"Fixed-width text files
"xml"XML files
"worddocument"Microsoft Word document
"html"HTML files

Use the "FileType" name-value pair argument when filename does not include the file extension, or when the extension is not one of these:

  • .txt, .dat, or .csv for text files

  • .xls, .xlsb, .xlsm, .xlsx, .xltm, .xltx, or .ods for spreadsheet files

  • .xml, for XML files

  • .docx for Microsoft Word document files

  • .html, .xhtml, or .htm for HTML files

Example: "FileType","text"

Option to read the first column as row names, specified as a numeric or logical 1 (true) or 0 (false).

  • Set ReadRowNames to true when the first column of the region to read contains the row names for the table.

  • Set ReadRowNames to false when the first column of the region to read contains data, not the row names for the table.

If both the ReadVariableNames and ReadRowNames name-value arguments are true, then readtable saves the name in the first column of the first row of the region to read as the first dimension name in the property T.Properties.DimensionNames.

If you specify the ReadRowNames argument in addition to an import options object, then the readtable behavior changes based on the specification:

  • If ReadRowNames is true, then read the row names from the specified file by using the RowNamesColumn (DelimitedTextImportOptions, FixedWidthImportOptions), RowNamesRange (SpreadsheetImportOptions), or RowNamesSelector (XMLImportOptions) property of the respective import options object.

  • If ReadRowNames is false, then do not import row names.

If you use the import options syntax without specifying ReadRowNames, readtable uses the value associated with the import options object and its ReadRowNames name-value argument.

Example: "ReadRowNames",true

Field delimiter character, specified as Delimiter and a character vector, a cell array of character vectors, or a string. Specify Delimiter using any valid character such as a comma "," or a period ".".

This table lists some commonly used field delimiter characters.

Specifier

Field Delimiter

","

"comma"

Comma

" "

"space"

Space

"\t"

"tab"

Tab

";"

"semi"

Semicolon

"|"

"bar"

Vertical bar

unspecified

If unspecified, readtable automatically detects the delimiter.

To treat consecutive delimiters as a single delimiter, specify Delimiter as a cell array of character vectors. In addition, you must also specify the MultipleDelimsAsOne option.

Example: "Delimiter","," or "Delimiter","comma"

Procedure to manage leading delimiters in a delimited text file, specified as one of the values in this table.

Leading Delimiters RuleBehavior
"keep"Keep the delimiter.
"ignore"Ignore the delimiter.
"error"Return an error and abort the import operation.

Example: "LeadingDelimitersRule","keep"

Procedure to manage trailing delimiters in a delimited text file, specified as one of the values in this table.

Trailing Delimiters RuleBehavior
"keep"Keep the delimiter.
"ignore"Ignore the delimiter.
"error"Return an error and abort the import operation.

Example: "TrailingDelimitersRule","keep"

Procedure to handle consecutive delimiters in a delimited text file, specified as one of the values in this table.

Consecutive Delimiters RuleBehavior
"split"Split the consecutive delimiters into multiple fields.
"join"Join the delimiters into one delimiter.
"error"Return an error and abort the import operation.

Example: "ConsecutiveDelimitersRule","split"

Multiple delimiter handling, specified as MultipleDelimsAsOne and either true or false. If true, then readtable treats consecutive delimiters as a single delimiter. Repeated delimiters separated by white-space are also treated as a single delimiter. You must also specify the Delimiter option.

Example: "MultipleDelimsAsOne",1

Number of header lines to skip at the beginning of the file, specified as NumHeaderLines and either 0 or a positive integer. If unspecified, readtable automatically detects the number of lines to skip.

Example: "NumHeaderLines",2

Data Types: single | double

Placeholder text to treat as an empty value, specified as "TreatAsMissing" and a character vector, cell array of character vectors, string scalar, or string array. Table elements corresponding to these characters are set to NaN.

"TreatAsMissing" only applies to numeric columns in the table, and readtable does not accept numeric literals, such as "-99".

Example: "TreatAsMissing","N/A" or "TreatAsMissing","N/A" sets N/A within numeric columns to NaN.

Example: "TreatAsMissing",{'.','NA','N/A'} or "TreatAsMissing",[".","NA","N/A"] sets ., NA and N/A within numeric columns to NaN.

Procedure to manage missing data, specified as one of the values in this table. Data is considered missing if an expected field in a row does not exist. Because missing fields cause subsequent elements of a row to shift fields, the missing fields are interpreted at the end of the row.

Missing RuleBehavior
"fill"

Replace missing data with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"error"Stop importing and display an error message showing the missing record and field.
"omitrow"Omit rows that contain missing data.
"omitvar"Omit variables that contain missing data.

Example: "MissingRule","omitrow"

Type for imported text data, specified as one of these values:

  • "string" — Import text data as string arrays.

  • "char" — Import text data as character vectors.

Example: "TextType","char"

Type for imported date and time data, specified as DatetimeType and one of these values: "datetime", "text", or "exceldatenum". The value "exceldatenum" is applicable only for spreadsheet files, and is not valid for text files.

ValueType for Imported Date and Time Data
"datetime"

MATLAB datetime data type

For more information, see datetime.

"text"

If "DatetimeType" is specified as "text", then the type for imported date and time data depends on the value specified in the "TextType" parameter:

  • If "TextType" is set to "char", then readtable returns dates as a cell array of character vectors.

  • If "TextType" is set to "string", then readtable returns dates as an array of strings.

"exceldatenum"

Excel serial date numbers

A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see Differences between the 1900 and the 1904 date system in Excel.

Example: "DatetimeType","datetime"

Flag to preserve variable names, specified as either "modify" or "preserve".

  • "modify" — Convert invalid variable names (as determined by the isvarname function) to valid MATLAB identifiers.

  • "preserve" — Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.

Starting in R2019b, variable names and row names can include any characters, including spaces and non-ASCII characters. Also, they can start with any characters, not just letters. Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname function). To preserve these variable names and row names, set the value of VariableNamingRule to "preserve". Variable names are not refreshed when the value of VariableNamingRule is changed from "modify" to "preserve".

Example: "VariableNamingRule","preserve"

Procedure to handle import errors, specified as one of the values in this table. An import error occurs when readtable is unable to convert a text element to the expected data type.

Import Error RuleBehavior
"fill"

Replace the data where the error occurred with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"error"Stop importing and display an error message showing the error-causing record and field.
"omitrow"Omit rows where errors occur.
"omitvar"Omit variables where errors occur.

Example: "ImportErrorRule","omitvar"

HTTP or HTTPS request options, specified as a weboptions object. The weboptions object determines how to import data when the specified filename is an internet URL containing the protocol type "http://" or "https://".

Indicator for reading the first row as variable names, specified as ReadVariableNames and either true, false, 1, or 0. If unspecified, readtable automatically detects the presence of variable names.

Indicator

Description

true

Use when the first row of the region to read contains the variable names for the table. readtable creates a variable, with the detected variable name, for each column in T.

false

Use when the first row of the region to read contains data in the table. readtable creates default variable names of the form "Var1",...,"VarN", where N is the number of variables.

unspecified When left unspecified, readtable automatically detects true or false and proceeds accordingly.

Note: If both the "ReadVariableNames" and "ReadRowNames" logical indicators are true, then readtable saves the name in the first column of the first row of the region to read as the first dimension name in the property, T.Properties.DimensionNames.

If you specify the ReadVariableNames argument in addition to opts the import options, then the readtable behavior changes based on the specification:

  • If ReadVariableNames is true, then read the variable names from the specified file by using the VariableNamesRange or the VariableNamesLine property of the import options object.

  • If ReadVariableNames is false, then read the variable names from the VariableNames property of the import options object.

Example: "ReadVariableNames",true

Expected number of variables, specified as ExpectedNumVariables and a positive integer. If unspecified, readtable automatically detects the number of variables.

Example: "ExpectedNumVariables",5

Data Types: single | double

Field widths of variables in a fixed-width text file, specified as a vector of positive integer values. Each positive integer in the vector corresponds to the number of characters in a field that makes up the variable. The VariableWidths property contains an entry corresponding to each variable specified in the VariableNames property.

Example: "VariableWidths",[10,7,4,26,7]

Characters to treat as white space, specified as a string scalar or character vector containing one or more characters.

This table shows how to represent special characters that you cannot enter using ordinary text.

Special Character

Representation

Percent character

%%

Backslash

\\

Alarm

\a

Backspace

\b

Form feed

\f

New line

\n

Carriage return

\r

Horizontal tab

\t

Vertical tab

\v

Character whose Unicode® numeric value can be represented by the hexadecimal number, N

\xN

Character whose Unicode numeric value can be represented by the octal number, N

\N

Example: "Whitespace"," _"

Example: "Whitespace","?!.,"

Procedure to handle empty lines in the data, specified as one of the values in this table. readtable interprets white space as empty. A line is considered empty if it contains no fields. A line is defined by two end-of-line characters.

Empty Line RuleBehavior
"skip"Skip the empty lines.
"read"Import the empty lines. readtable parses an empty line using the values specified in VariableWidths, VariableOptions, MissingRule, and other relevant properties, such as Whitespace.
"error"Display an error message and cancel the import operation.

Example: "EmptyLineRule","skip"

Variable names location, specified as a positive scalar integer. The VariableNamesLine property specifies the line number where variable names are located.

If VariableNamesLine is specified as 0, then do not import the variable names. Otherwise, import the variable names from the specified line.

Example: "VariableNamesLine",6

Data Types: single | double | uint8 | uint16 | uint32 | uint64

Procedure to handle partial fields in the data, specified as one of the values in this table. A field is considered partially filled if it terminates before the end of the expected width. This applies only to fields with fixed widths.

Partial Field RuleBehavior
"keep"

Keep the partial field data and convert the text to the appropriate data type.

In some cases, when readtable is unable to interpret the partial data, a conversion error can occur.

"fill"

Replace missing data with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"omitrow"Omit rows that contain partial data.
"omitvar"Omit variables that contain partial data.
"wrap"Begin reading the next line of characters.
"error"Display an error message and cancel the import operation.

Example: "PartialFieldRule","keep"

Variable units location, specified as a positive scalar integer. The VariableUnitsLine property specifies the line number where variable units are located.

If VariableUnitsLine is specified as 0, then do not import the variable units. Otherwise, import the variable units from the specified line.

Example: "VariableUnitsLine",8

Data Types: single | double | uint8 | uint16 | uint32 | uint64

Variable description location, specified as a positive scalar integer. The VariableDescriptionsLine property specifies the line number where variable descriptions are located.

If VariableDescriptionsLine is specified as 0, then do not import the variable descriptions. Otherwise, import the variable descriptions from the specified line.

Example: "VariableDescriptionsLine",7

Data Types: single | double | uint8 | uint16 | uint32 | uint64

Procedure to handle extra columns in the data, specified as one of the values in this table. Columns are considered extra if a row has more columns than expected.

Extra Columns RuleBehavior
"addvars"

To import extra columns, create new variables. If there are N extra columns, then import new variables as "ExtraVar1","ExtraVar2",...,"ExtraVarN".

The extra columns are imported as text with data type char.

"ignore"Ignore the extra columns of data.
"wrap"Wrap the extra columns of data to new records. This action does not change the number of variables.
"error"Display an error message and cancel the import operation.

Example: "ExtraColumnsRule","addvars"

Column format of the file, specified as Format and a character vector or a string scalar having one or more conversion specifiers, or "auto". The conversion specifiers are the same as the specifiers accepted by the textscan function.

Specifying the format can significantly improve speed for some large files. If you do not specify a value for Format, then readtable uses %q to interpret nonnumeric columns. The %q specifier reads the text and omits double quotation marks (") if appropriate.

  • If you do not specify the "Format" name-value pair, then the readtable function behaves as though you have used the results of the detectImportOptions function to import the data. For more information on the consequences of this behavior, see Compatibility Considerations.

  • If you specify "Format","auto", then the variables created are double arrays, cell array of character vectors, or datetime arrays, depending on the data. If the entire column is numeric, variables are imported as double. If any element in a column is not numeric, the variables are imported as cell arrays of character vectors, or as datetime arrays if the values represent dates and times.

Example: "Format","auto"

Returned value for empty numeric fields in delimited text files, specified as EmptyValue and a numeric scalar.

Example: "EmptyValue",0

Logical indicator determining data concatenation, specified as CollectOutput and either true or false. If true, then readtable concatenates consecutive output cells of the same fundamental MATLAB class into a single array.

Example: "CollectOutput",true

Symbols designating text to ignore, specified as CommentStyle and a character vector, cell array of character vectors, string scalar, or string array.

For example, specify a character such as "%" to ignore text following the symbol on the same line. Specify a cell array of two character vectors, such as {'/*','*/'}, to ignore any text between those sequences.

MATLAB checks for comments only at the start of each field, not within a field.

Example: "CommentStyle",{'/*','*/'}

Exponent characters, specified as ExponentCharacter and a character vector or string scalar. The default exponent characters are e, E, d, and D.

Example: "ExponentCharacter","eE"

End-of-line characters, specified as LineEnding and a character vector or string scalar. The character vector must be "\r\n" or it must specify a single character. Common end-of-line characters are a newline character ("\n") or a carriage return ("\r"). If you specify "\r\n", then readtable treats any of \r, \n, and the combination of the two (\r\n) as end-of-line characters.

The default end-of-line sequence is \n, \r, or \r\n, depending on the contents of your file.

If there are missing values and an end-of-line sequence at the end of the last line in a file, then readtable returns empty values for those fields. This ensures that individual cells in output cell array, C, are the same size.

Example: "LineEnding",":"

Locale for reading dates, specified as DateLocale and a character vector or a string scalar of the form xx_YY, where:

  • YY is an uppercase ISO 3166-1 alpha-2 code indicating a country.

  • xx is a lowercase ISO 639-1 two-letter code indicating a language.

This table lists some common values for the locale.

Locale LanguageCountry
"de_DE"GermanGermany
"en_GB"EnglishUnited Kingdom
"en_US"EnglishUnited States
"es_ES"SpanishSpain
"fr_FR"FrenchFrance
"it_IT"ItalianItaly
"ja_JP"JapaneseJapan
"ko_KR"KoreanKorea
"nl_NL"DutchNetherlands
"zh_CN"Chinese (simplified)China

When using the %D format specifier to read text as datetime values, use DateLocale to specify the locale in which readtable should interpret month and day-of-week names and abbreviations.

If you specify the DateLocale argument in addition to opts the import options, then readtable uses the specified value for the DateLocale argument, overriding the locale defined in the import options.

Example: "DateLocale","ja_JP"

Characters indicating the decimal separator in numeric variables, specified as a character vector or string scalar. The readtable uses the characters specified in the DecimalSeparator name-value argument to distinguish the integer part of a number from the decimal part.

When converting to integer data types, numbers with a decimal part are rounded to the nearest integer.

Example: If name-value pair is specified as "DecimalSeparator",",", then readtable imports the text "3,14159" as the number 3.14159.

Characters that indicate the thousands grouping in numeric variables, specified as a character vector or string scalar. The thousands grouping characters act as visual separators, grouping the number at every three place values. The readtable uses the characters specified in the ThousandsSeparator name-value argument to interpret the numbers being imported.

Example: If name-value pair is specified as "ThousandsSeparator",",", then readtable imports the text "1,234,000" as 1234000.

Remove nonnumeric characters from a numeric variable, specified as a logical true or false.

Example: If name-value pair is specified as "TrimNonNumeric",true, then readtable reads "$500/-" as 500.

Data Types: logical

Character encoding scheme associated with the file, specified as Encoding and "system" or a standard character encoding scheme name. When you do not specify any encoding, the readtable function uses automatic character set detection to determine the encoding when reading the file.

If you specify the "Encoding" argument in addition to the import options, then the readtable function uses the specified value for "Encoding", overriding the encoding defined in the import options.

Example: "Encoding","UTF-8" uses UTF-8 as the encoding.

Example: "Encoding","system" uses the system default encoding.

Output data type of duration data from text files, specified as DurationType and either "duration" or "text".

ValueType for Imported Duration Data
"duration"

MATLAB duration data type

For more information, see duration.

"text"

If "DurationType" is specified as "text", then the type for imported duration data depends on the value specified in the "TextType" parameter:

  • If "TextType" is "char", then readtable returns duration data as a cell array of character vectors.

  • If "TextType" is "string", then readtable returns duration data as an array of strings.

Example: "DurationType","text"

Output data type of hexadecimal data, specified as HexType and one of the values listed in the table.

The input file represents hexadecimal values as text, using either 0x or 0X as a prefix and the characters 0-9, a-f, and A-F as digits. (Uppercase and lowercase letters represent the same digits—for example, "0xf" and "0xF" both represent 15.)

readtable converts the hexadecimal values to the data type specified by the value of "HexType".

Value of "HexType"

Data Type of Output Table Variables

"auto"

data type detected automatically

"text"

unaltered input text

"int8"

8-bit integer, signed

"int16"

16-bit integer, signed

"int32"

32-bit integer, signed

"int64"

64-bit integer, signed

"uint8"

8-bit integer, unsigned

"uint16"

16-bit integer, unsigned

"uint32"

32-bit integer, unsigned

"uint64"

64-bit integer, unsigned

Example: "HexType","uint16" converts text representing hexadecimal values (such as "0xFF") to unsigned 16-bit integers (such as 255) in the output table.

Output data type of binary data, specified as BinaryType and one of the values listed in the table.

The input file represents binary values as text, using either 0b or 0B as a prefix and the characters 0 and 1 as digits.

readtable converts the binary values to the data type specified by the value of "BinaryType".

Value of "BinaryType"

Data Type of Output Table Variables

"auto"

data type detected automatically

"text"

unaltered input text

"int8"

8-bit integer, signed

"int16"

16-bit integer, signed

"int32"

32-bit integer, signed

"int64"

64-bit integer, signed

"uint8"

8-bit integer, unsigned

"uint16"

16-bit integer, unsigned

"uint32"

32-bit integer, unsigned

"uint64"

64-bit integer, unsigned

Example: "BinaryType","uint16" converts text representing binary values (such as "0b11111111") to unsigned 16-bit integers (such as 255) in the output table.

Spreadsheet Files

collapse all

Type of file, specified as one of these values.

ValueFile Type
"spreadsheet"Spreadsheet files
"text"Text files
"delimitedtext"Delimited text files
"fixedwidth"Fixed-width text files
"xml"XML files
"worddocument"Microsoft Word document
"html"HTML files

Use the "FileType" name-value pair argument when filename does not include the file extension, or when the extension is not one of these:

  • .txt, .dat, or .csv for text files

  • .xls, .xlsb, .xlsm, .xlsx, .xltm, .xltx, or .ods for spreadsheet files

  • .xml, for XML files

  • .docx for Microsoft Word document files

  • .html, .xhtml, or .htm for HTML files

Example: "FileType","text"

Option to read the first column as row names, specified as a numeric or logical 1 (true) or 0 (false).

  • Set ReadRowNames to true when the first column of the region to read contains the row names for the table.

  • Set ReadRowNames to false when the first column of the region to read contains data, not the row names for the table.

If both the ReadVariableNames and ReadRowNames name-value arguments are true, then readtable saves the name in the first column of the first row of the region to read as the first dimension name in the property, T.Properties.DimensionNames.

If you specify the ReadRowNames argument in addition to an import options object, then the readtable behavior changes based on the specification:

  • If ReadRowNames is true, then read the row names from the specified file by using the RowNamesColumn (DelimitedTextImportOptions, FixedWidthImportOptions), RowNamesRange (SpreadsheetImportOptions), or RowNamesSelector (XMLImportOptions) property of the respective import options object.

  • If ReadRowNames is false, then do not import row names.

If you use the import options syntax without specifying ReadRowNames, readtable uses the value associated with the import options object and its ReadRowNames name-value argument.

Example: "ReadRowNames",true

Placeholder text to treat as an empty value, specified as TreatAsMissing and a character vector, cell array of character vectors, string scalar, or string array. Table elements corresponding to these characters are set to NaN.

TreatAsMissing only applies to numeric columns in the table, and readtable does not accept numeric literals, such as "-99".

Example: "TreatAsMissing","N/A" or "TreatAsMissing","N/A" sets N/A within numeric columns to NaN.

Example: "TreatAsMissing",{'.','NA','N/A'} or "TreatAsMissing",[".","NA","N/A"] sets ., NA and N/A within numeric columns to NaN.

Procedure to manage missing data, specified as one of the values in this table. Data is considered missing if the expected field in the row has no data and the field type is blank or empty.

Missing RuleBehavior
"fill"

Replace missing data with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"error"Stop importing and display an error message showing the missing record and field.
"omitrow"Omit rows that contain missing data.
"omitvar"Omit variables that contain missing data.

Example: "MissingRule","omitrow"

Portion of the worksheet to read, indicated as a rectangular area specified as a character vector or string scalar in one of the following forms.

Ways to specify Range Description

"Cell" or [row col]

Starting Cell

Specify the starting cell for the data as a character vector or string scalar or a two element numeric vector.

  • Character vector or string scalar containing a column letter and row number using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

  • Two element numeric vector of the form [row col] indicating the starting row and column.

Using the starting cell, readtable automatically detects the extent of the data by beginning the import at the start cell and ending at the last empty row or footer range.

Example: "A5" or [5 1]

"Corner1:Corner2"

Rectangular Range

Specify the range using the syntax "Corner1:Corner2", where Corner1 and Corner2 are two opposing corners that define the region. For example, "D2:H4" represents the 3-by-5 rectangular region between the two corners D2 and H4 on the worksheet. The "Range" name-value pair argument is not case-sensitive, and uses Excel A1 reference style (see Excel help).

Example: "Range","D2:H4"

""

Unspecified or Empty

If unspecified, readtable automatically detects the used range.

Example: "Range",""

Note: Used Range refers to the rectangular portion of the spreadsheet that actually contains data. readtable automatically detects the used range by trimming any leading and trailing rows and columns that do not contain data. Text that is only white space is considered data and is captured within the used range.

"Row1:Row2"

Row Range

You can identify range by specifying the beginning and ending rows using Excel row designators. Then readtable automatically detects the used column range within the designated rows. For instance, readtable interprets the range specification "1:7" as an instruction to read all columns in the used range in rows 1 through 7 (inclusive).

Example: "Range","1:7"

"Column1:Column2"

Column Range

You can identify range by specifying the beginning and ending columns using Excel column designators. Then readtable automatically detects the used row range within the designated columns. For instance, readtable interprets the range specification "A:F" as an instruction to read all rows in the used range in columns A through F (inclusive).

Example: "Range","A:F"

"NamedRange"

Named Range in Excel

In Excel, you can create names to identify ranges in the spreadsheet. For instance, you can select a rectangular portion of the spreadsheet and call it "myTable". If such named ranges exist in a spreadsheet, then readtable can read that range using its name.

Example: "Range","myTable"

Example: "Range", "A1:F10"

Example: "Range", "A1:F10"—

Location of data to be imported, specified as a character vector, string scalar, cell array of character vectors, string array, positive scalar integer or an N-by-2 array of positive scalar integers. Specify DataRange using one of these forms.

Specified byBehavior

"Cell" or n

Starting Cell or Starting Row

Specify the starting cell for the data, using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

Using the starting cell, readtable automatically detects the extent of the data, by beginning the import at the start cell and ending at the last empty row or footer range.

Alternatively, specify the first row containing the data using the positive scalar row index.

Using the specified row index, readtable automatically detects the extent of the data by reading from the specified first row to the end of the data or the footer range.

Example: "A5" or 5

"Corner1:Corner2"

Rectangular Range

Specify the exact range to read using the rectangular range form, where Corner1 and Corner2 are two opposing corners that define the region to read.

readtable only reads the data contained in the specified range. Any empty fields within the specified range are imported as missing cells.

The number of columns must match the number specified in the NumVariables property.

Example: "A5:K50"

"Row1:Row2" or "Column1:Column2"

Row Range or Column Range

Specify the range by identifying the beginning and ending rows using Excel row numbers.

Using the specified row range, readtable automatically detects the column extent by reading from the first nonempty column to the end of the data, and creates one variable per column.

Example: "5:500"

Alternatively, specify the range by identifying the beginning and ending columns using Excel column letters or numbers.

Using the specified column range, the import function automatically detects the row extent by reading from the first nonempty row to the end of the data or the footer range.

The number of columns in the specified range must match the number specified in the NumVariables property.

Example: "A:K"

[n1 n2; n3 n4;...]

Multiple Row Ranges

Specify multiple row ranges to read with an N-by-2 array containing N different row ranges.

A valid array of multiple row ranges must:

  • Specify line ranges in an increasing order, that is the first row range specified in the array appears in the file before the other row ranges.

  • Contain only non-overlapping row ranges.

Use of Inf is only supported to indicate the last range in the numeric array specifying multiple row ranges. For example, [1 3; 5 6; 8 Inf].

Example: [1 3; 5 6; 8 Inf]

""

Unspecified or Empty

Do not fetch any data.

Example: ""

Example: "DataRange", "B2:H15"

Data Types: char | string | cell | single | double

Location of row names, specified as a character vector, string scalar, positive scalar integer, or an empty character array. Specify RowNamesRange as one of the values in this table.

Specified byBehavior

"Cell"

Specify the starting cell for the data, using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

readtable identifies a name for each variable in the data.

Example: "A5"

"Corner1:Corner2"

Rectangular Range

Specify the exact range to read using the rectangular range form, where Corner1 and Corner2 are two opposing corners that define the region to read.

The number of rows contained in RowNamesRange must match the number of data rows, and the range indicated by RowNamesRange must span only one column.

Example: "A5:A50"

"Row1:Row2"

Row Range

Specify range by identifying the beginning and ending rows using Excel row numbers.

Row names must be in a single column.

Example: "5:50"

n

Number Index

Specify the column containing the row names using a positive scalar column index.

Example: 5

""

Unspecified or Empty

Indicate that there are no row names.

Example: ""

Example: "RowNamesRange", "A1:H1"

Data Types: char | single | double

Location of variable names, specified as a character vector, string scalar, positive scalar integer, or an empty character array. Specify VariableNamesRange as one of the values in this table.

Specified byBehavior

"Cell"

Specify the starting cell for the data, using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

readtable reads a name for each variable in the data.

Example: "A5"

"Corner1:Corner2"

Rectangular Range

Specify the exact range to read using the rectangular range form, where Corner1 and Corner2 are two opposing corners that define the region to read.

The number of columns must match the number specified in the NumVariables property, and the range must span only one row.

Example: "A5:K5"

"Row1:Row2"

Row Range

Specify range by identifying the beginning and ending rows using Excel row numbers.

Must be a single row.

Example: "5:5"

n

Number Index

Specify the row containing the variable names using a positive scalar row index.

Example: 5

""

Unspecified or Empty

Indicate that there are no variable names.

Example: ""

Example: "VariableNamesRange", "A1:A15"

Data Types: char | single | double

Location of variable units, specified as a character vector, string scalar, positive scalar integer, or an empty character array. Specify VariableUnitsRange as one of the values in this table.

Specified byBehavior

"Cell"

Specify the starting cell for the data, using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

readtable reads a unit for each variable in the data.

Example: "A5"

"Corner1:Corner2"

Rectangular Range

Specify the exact range to read using the rectangular range form, where Corner1 and Corner2 are two opposing corners that define the region to read.

The number of columns must match the number specified in the NumVariables property, and the range must span only one row.

Example: "A5:K5"

"Row1:Row2"

Row Range

Specify range by identifying the beginning and ending rows using Excel row numbers.

Must be a single row.

Example: "5:5"

n

Number Index

Specify the row containing the data units using a positive scalar row index.

Example: 5

""

Unspecified or Empty

Indicate that there are no variable units.

Example: ""

Example: "VariableUnitsRange", "A1:A5"

Data Types: char | string | single | double

Location of variable descriptions, specified as a character vector, string scalar, positive scalar integer, or an empty character array. Specify VariableDescriptionRange as one of the values in this table.

Specified byBehavior

"Cell"

Specify the starting cell for the data, using Excel A1 notation. For example, A5 is the identifier for the cell at the intersection of column A and row 5.

readtable reads a description for each variable in the data.

Example: "A5"

"Corner1:Corner2"

Rectangular Range

Specify the exact range to read using the rectangular range form, where Corner1 and Corner2 are two opposing corners that define the region to read.

The number of columns must match the number specified in the NumVariables property, and the range must span only one row.

Example: "A5:K5"

"Row1:Row2"

Row Range

Specify range by identifying the beginning and ending rows using Excel row numbers.

Must be a single row.

Example: "5:5"

n

Number Index

Specify the row containing the descriptions using a positive scalar row index.

Example: 5

""

Unspecified or Empty

Indicate that there are no variable descriptions.

Example: ""

Example: "VariableDescriptionsRange", "B1:B15"

Data Types: char | string | single | double

Type for imported text data, specified as one of these values:

  • "string" — Import text data as string arrays.

  • "char" — Import text data as character vectors.

Example: "TextType","char"

Type for imported date and time data, specified as DatetimeType and one of these values: "datetime", "text", or "exceldatenum". The value "exceldatenum" is applicable only for spreadsheet files, and is not valid for text files.

ValueType for Imported Date and Time Data
"datetime"

MATLAB datetime data type

For more information, see datetime.

"text"

If "DatetimeType" is specified as "text", then the type for imported date and time data depends on the value specified in the "TextType" parameter:

  • If "TextType" is set to "char", then readtable returns dates as a cell array of character vectors.

  • If "TextType" is set to "string", then readtable returns dates as an array of strings.

"exceldatenum"

Excel serial date numbers

A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see Differences between the 1900 and the 1904 date system in Excel.

Example: "DatetimeType","datetime"

Flag to preserve variable names, specified as either "modify" or "preserve".

  • "modify" — Convert invalid variable names (as determined by the isvarname function) to valid MATLAB identifiers.

  • "preserve" — Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.

Starting in R2019b, variable names and row names can include any characters, including spaces and non-ASCII characters. Also, they can start with any characters, not just letters. Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname function). To preserve these variable names and row names, set the value of VariableNamingRule to "preserve". Variable names are not refreshed when the value of VariableNamingRule is changed from "modify" to "preserve".

Example: "VariableNamingRule","preserve"

Procedure to handle import errors, specified as one of the values in this table. An import error occurs when readtable is unable to convert data to the expected data type or the cell has the Microsoft error data type.

Import Error RuleBehavior
"fill"

Replace the data where the error occurred with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"error"Stop importing and display an error message showing the error-causing record and field.
"omitrow"Omit rows where errors occur.
"omitvar"Omit variables where errors occur.

Example: "ImportErrorRule","omitvar"

HTTP or HTTPS request options, specified as a weboptions object. The weboptions object determines how to import data when the specified filename is an internet URL containing the protocol type "http://" or "https://".

Indicator for reading the first row as variable names, specified as ReadVariableNames and either true, false, 1, or 0. If unspecified, readtable automatically detects the presence of variable names.

Indicator

Description

true

Use when the first row of the region to read contains the variable names for the table. readtable creates a variable, with the detected variable name, for each column in T.

false

Use when the first row of the region to read contains data in the table. readtable creates default variable names of the form "Var1",...,"VarN", where N is the number of variables.

unspecified When left unspecified, readtable automatically detects true or false and proceeds accordingly.

Note: If both the "ReadVariableNames" and "ReadRowNames" logical indicators are true, then readtable saves the name in the first column of the first row of the region to read as the first dimension name in the property, T.Properties.DimensionNames.

If you specify the ReadVariableNames argument in addition to opts the import options, then the readtable behavior changes based on the specification:

  • If ReadVariableNames is true, then read the variable names from the specified file by using the VariableNamesRange or the VariableNamesLine property of the import options object.

  • If ReadVariableNames is false, then read the variable names from the VariableNames property of the import options object.

Example: "ReadVariableNames",true

Expected number of variables, specified as ExpectedNumVariables and a positive integer. If unspecified, readtable automatically detects the number of variables.

Example: "ExpectedNumVariables",5

Data Types: single | double

Worksheet to read, specified as Sheet and a positive integer indicating the worksheet index or a character vector or string scalar containing the worksheet name. The worksheet name cannot contain a colon (:). To determine the names of sheets in a spreadsheet file, use sheets = sheetnames(filename). For more information, see sheetnames.

If you specify the Sheet argument in addition to opts the import options, then the readtable function uses the specified value for Sheet argument, overriding the sheet name defined in the import options.

Example: "Sheet", 2

Example: 'Sheet', 'MySheetName'

Example: "Sheet", "MySheetName"

Data Types: char | string | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Flag to start an instance of Microsoft Excel for Windows when reading spreadsheet data, specified as UseExcel and either true, or false.

You can set the "UseExcel" parameter to one of these values:

  • true — readtable starts an instance of Microsoft Excel when reading the file.

  • false — readtable does not start an instance of Microsoft Excel when reading the file. When operating in this mode, readtable functionality differs in the support of file formats and interactive features, such as formulas and macros.

UseExcel

true

false

Supported file formats

.xls, .xlsx, .xlsm, .xltx, .xltm, .xlsb, .ods

.xls, .xlsx, .xlsm, .xltx, .xltm

Support for interactive features, such as formulas and macros

Yes

No

When reading from spreadsheet files on Windows platforms, if you want to start an instance of Microsoft Excel, then set the "UseExcel" parameter to true.

Example: "UseExcel",true

XML Files

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Type of file, specified as one of these values.

ValueFile Type
"spreadsheet"Spreadsheet files
"text"Text files
"delimitedtext"Delimited text files
"fixedwidth"Fixed-width text files
"xml"XML files
"worddocument"Microsoft Word document
"html"HTML files

Use the "FileType" name-value pair argument when filename does not include the file extension, or when the extension is not one of these:

  • .txt, .dat, or .csv for text files

  • .xls, .xlsb, .xlsm, .xlsx, .xltm, .xltx, or .ods for spreadsheet files

  • .xml, for XML files

  • .docx for Microsoft Word document files

  • .html, .xhtml, or .htm for HTML files

Example: "FileType","text"

Option to read the first column as row names, specified as a numeric or logical 1 (true) or 0 (false).

  • Set ReadRowNames to true when the first column of the region to read contains the row names for the table.

  • Set ReadRowNames to false when the first column of the region to read contains data, not the row names for the table.

If both the ReadVariableNames and ReadRowNames name-value arguments are true, then readtable saves the name in the first column of the first row of the region to read as the first dimension name in the property, T.Properties.DimensionNames.

If you specify the ReadRowNames argument in addition to an import options object, then the readtable behavior changes based on the specification:

  • If ReadRowNames is true, then read the row names from the specified file by using the RowNamesColumn (DelimitedTextImportOptions, FixedWidthImportOptions), RowNamesRange (SpreadsheetImportOptions), or RowNamesSelector (XMLImportOptions) property of the respective import options object.

  • If ReadRowNames is false, then do not import row names.

If you use the import options syntax without specifying ReadRowNames, readtable uses the value associated with the import options object and its ReadRowNames name-value argument.

Example: "ReadRowNames",true

Placeholder text to treat as an empty value, specified as TreatAsMissing and a character vector, cell array of character vectors, string scalar, or string array. Table elements corresponding to these characters are set to NaN.

"TreatAsMissing" only applies to numeric columns in the table, and readtable does not accept numeric literals, such as "-99".

Example: 'TreatAsMissing','N/A' or "TreatAsMissing","N/A" sets N/A within numeric columns to NaN.

Example: 'TreatAsMissing',{'.','NA','N/A'} or "TreatAsMissing",[".","NA","N/A"] sets ., NA and N/A within numeric columns to NaN.

Procedure to manage missing data, specified as one of the values in this table. Data is considered missing if an expected node does not exist.

Missing RuleBehavior
"fill"

Replace missing data with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"error"Stop importing and display an error message showing the missing record and field.
"omitrow"Omit rows that contain missing data.
"omitvar"Omit variables that contain missing data.

Example: "MissingRule","omitrow"

Type for imported text data, specified as one of these values:

  • "string" — Import text data as string arrays.

  • "char" — Import text data as character vectors.

Example: "TextType","char"

Type for imported date and time data, specified as DatetimeType and one of these values: "datetime", "text", or "exceldatenum". The value "exceldatenum" is applicable only for spreadsheet files, and is not valid for text files.

ValueType for Imported Date and Time Data
"datetime"

MATLAB datetime data type

For more information, see datetime.

"text"

If "DatetimeType" is specified as "text", then the type for imported date and time data depends on the value specified in the "TextType" parameter:

  • If "TextType" is set to "char", then readtable returns dates as a cell array of character vectors.

  • If "TextType" is set to "string", then readtable returns dates as an array of strings.

"exceldatenum"

Excel serial date numbers

A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see Differences between the 1900 and the 1904 date system in Excel.

Example: "DatetimeType","datetime"

Flag to preserve variable names, specified as either "modify" or "preserve".

  • "modify" — Convert invalid variable names (as determined by the isvarname function) to valid MATLAB identifiers.

  • "preserve" — Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.

Starting in R2019b, variable names and row names can include any characters, including spaces and non-ASCII characters. Also, they can start with any characters, not just letters. Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname function). To preserve these variable names and row names, set the value of VariableNamingRule to "preserve". Variable names are not refreshed when the value of VariableNamingRule is changed from "modify" to "preserve".

Example: "VariableNamingRule","preserve"

Procedure to handle import errors, specified as one of the values in this table. An import error occurs when readtable is unable to convert text to the expected data type.

Import Error RuleBehavior
"fill"

Replace the data where the error occurred with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"error"Stop importing and display an error message showing the error-causing record and field.
"omitrow"Omit rows where errors occur.
"omitvar"Omit variables where errors occur.

Example: "ImportErrorRule","omitvar"

HTTP or HTTPS request options, specified as a weboptions object. The weboptions object determines how to import data when the specified filename is an internet URL containing the protocol type "http://" or "https://".

Attribute suffix, specified as AttributeSuffix and either a character vector or string scalar. This argument specifies the suffix the reading function appends to all table variables that correspond to attributes in the input XML file. If you do not specify AttributeSuffix, then the reading function defaults to appending the suffix "Attribute" to all variable names corresponding to attributes in the input XML file.

Example: "AttributeSuffix","_att"

Import attributes, specified as ImportAttributes and either 1 (true) or 0 (false). If you specify false, then the reading function will not import the XML attributes in the input file as variables in the output table.

Example: "ImportAttributes",false

Table row XML node name, specified as RowNodeName and either a character vector or string scalar. This argument specifies the XML node name that delineates rows of the output table.

Example: "RowNodeName","XMLNodeName"

Table row XPath expression, specified as a character vector or string scalar that the reading function uses to select individual rows of the output table. You must specify RowSelector as a valid XPath version 1.0 expression.

Example: "RowSelector","/RootNode/ChildNode"

Table variable XML node names, specified as VariableNodeNames and either a cell array of character vectors or string array. This argument specifies the XML node name that the reading function uses to identify the XML nodes to read as variables in the output table.

Example: "VariableNodeNames",{'XMLNodeName1','XMLNodeName2'}

Example: 'VariableNodeNames',"XMLNodeName"

Example: 'VariableNodeNames',["XMLNodeName1","XMLNodeName2"]

Table variable XPath expressions, specified as a cell array of character vectors or string array that the reading function uses to select table variables. You must specify VariableSelectors as valid XPath version 1.0 expressions.

Use XPath selectors to specify which elements of the XML input document to import. For example, suppose you want to import the XML file myFile.xml, which has the following structure:

<data>
    <table category="ones">
        <var>1</var>
        <var>2</var>
    </table>
    <table category="tens">
        <var>10</var>
        <var>20</var>
    </table>
</data>

Selection OperationSyntaxExample
Select every node whose name matches the node you want to select, regardless of its location in the document.Prefix the name with two forward slashes (//).

To select every node named "var", use:

data = readtable("myFile.xml", "VariableSelectors", "//var")
Read the value of an attribute belonging to an element node.Prefix the attribute with an at sign (@).

To select the value of the category attribute of the table node, use:

data = readtable("myFile.xml", "VariableSelectors", "//table/@category")
Select a specific node in a set of nodes.Provide the index of the node you want to select in square brackets ([]).

To select the first var node of each table node, use:

data = readtable("myFile.xml", "VariableSelectors", "//var[1]")
Specify precedence of operations.Add parentheses around the expression you want to evaluate first.

To select the first value of each var node, use:

data = readtable("myFile.xml", "VariableSelectors", "//table/var[1]")

To select the first value of the first var node, use:

data = readtable("myFile.xml", "VariableSelectors", "(//table/var)[1]")

Table XML node name, specified as TableNodeName and either a character vector or string scalar. This argument specifies the node in the input structure that the reading function should read to a table.

Example: "TableNodeName","NodeName"

Variable units XPath, specified as a character vector or string scalar that the reading function uses to select the table variable units. You must specify VariableUnitsSelector as a valid XPath version 1.0 expression.

Example: "VariableUnitsSelector","/RootNode/ChildNode"

Variable descriptions XPath expression, specified as a character vector or string scalar that the reading function reads uses to select the table variable descriptions. You must specify VariableDescriptionsSelector as a valid XPath version 1.0 expression.

Example: "VariableDescriptionsSelector","/RootNode/ChildNode"

Table row names XPath expression, specified as a character vector or string scalar that the reading function uses to select the names of the table rows. You must specify RowNamesSelector as a valid XPath version 1.0 expression.

Example: "RowNamesSelector","/RootNode/ChildNode"

Procedure to handle repeated XML nodes in a given row of a table, specified as "addcol", "ignore", or "error".

Repeated Node Rule

Behavior

"addcol"

Add columns for the repeated nodes under the variable header in the table. Specifying the value of "RepeatedNodeRule" as "addcol" does not create a separate variable in the table for the repeated node.

"ignore"

Skip importing the repeated nodes.

"error"Display an error message and abort the import operation.

Example: "RepeatedNodeRule","ignore"

Set of registered XML namespace prefixes, specified as RegisteredNamespaces and an array of prefixes. The reading function uses these prefixes when evaluating XPath expressions on an XML file. Specify the namespace prefixes and their associated URLs as an Nx2 string array. RegisteredNamespaces can be used when you also evaluate an XPath expression specified by a selector name-value argument, such as StructSelector for readstruct, or VariableSelectors for readtable and readtimetable.

By default, the reading function automatically detects namespace prefixes to register for use in XPath evaluation, but you can also register new namespace prefixes using the RegisteredNamespaces name-value argument. You might register a new namespace prefix when an XML node has a namespace URL, but no declared namespace prefix in the XML file.

For example, evaluate an XPath expression on an XML file called example.xml that does not contain a namespace prefix. Specify "RegisteredNamespaces" as ["myprefix", ""] to assign the prefix myprefix to the URL .

T = readtable("example.xml", "VariableSelector", "/myprefix:Data",...
 "RegisteredNamespaces", ["myprefix", ""])

Example: "RegisteredNamespaces",["myprefix", ""]

Table data XPath expression, specified as a character vector or string scalar that the reading function uses to select the output table data. You must specify TableSelector as a valid XPath version 1.0 expression. Use XPath selectors to specify which elements of the XML input document to import.

Selection OperationSyntax
Select every node whose name matches the node you want to select, regardless of its location in the document.Prefix the name with two forward slashes (//).
Select the value of an attribute belonging to an element node.Prefix the attribute with an at sign (@).
Select a specific node in a set of nodes.Provide the index of the node you want to select in square brackets ([]).
Specify precedence of operations.Add parentheses around the expression you want to evaluate first.

Example: "myFile.xml", "TableSelector", "//table[1]"

Microsoft Word Document Files

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Type of file, specified as one of these values.

ValueFile Type
"spreadsheet"Spreadsheet files
"text"Text files
"delimitedtext"Delimited text files
"fixedwidth"Fixed-width text files
"xml"XML files
"worddocument"Microsoft Word document
"html"HTML files

Use the "FileType" name-value pair argument when filename does not include the file extension, or when the extension is not one of these:

  • .txt, .dat, or .csv for text files

  • .xls, .xlsb, .xlsm, .xlsx, .xltm, .xltx, or .ods for spreadsheet files

  • .xml, for XML files

  • .docx for Microsoft Word document files

  • .html, .xhtml, or .htm for HTML files

Example: "FileType","text"

Option to read the first column as row names,specified as a numeric or logical 1 (true) or 0 (false).

  • Set ReadRowNames to true when the first column of the region to read contains the row names for the table.

  • Set ReadRowNames to false when the first column of the region to read contains data, not the row names for the table.

If both the ReadVariableNames and ReadRowNames name-value arguments are true, then readtable saves the name in the first column of the first row of the region to read as the first dimension name in the property, T.Properties.DimensionNames.

If you specify the ReadRowNames argument in addition to an import options object, then the readtable behavior changes based on the specification:

  • If ReadRowNames is true, then read the row names from the specified file by using the RowNamesColumn (DelimitedTextImportOptions, FixedWidthImportOptions), RowNamesRange (SpreadsheetImportOptions), or RowNamesSelector (XMLImportOptions) property of the respective import options object.

  • If ReadRowNames is false, then do not import row names.

If you use the import options syntax without specifying ReadRowNames, readtable uses the value associated with the import options object and its ReadRowNames name-value argument.

Example: "ReadRowNames",true

Placeholder text to treat as an empty value, specified as TreatAsMissing and a character vector, cell array of character vectors, string scalar, or string array. Table elements corresponding to these characters are set to NaN.

"TreatAsMissing" only applies to numeric columns in the table, and readtable does not accept numeric literals, such as "-99".

Example: 'TreatAsMissing','N/A' or "TreatAsMissing","N/A" sets N/A within numeric columns to NaN.

Example: 'TreatAsMissing',{'.','NA','N/A'} or "TreatAsMissing",[".","NA","N/A"] sets ., NA and N/A within numeric columns to NaN.

Procedure to manage missing data, specified as one of the values in this table. Data is considered missing if an expected field in a row does not exist.

Missing RuleBehavior
"fill"

Replace missing data with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"error"Stop importing and display an error message showing the missing record and field.
"omitrow"Omit rows that contain missing data.
"omitvar"Omit variables that contain missing data.

Example: "MissingRule","omitrow"

Rule to apply to empty rows in the table, specified as one of the following:

  • "skip" – Skip empty rows.

  • "read" – Read empty rows.

  • "error" – Ignore empty rows during table detection and error when reading.

Example: "EmptyRowRule","read"

Rule to apply to empty columns in the table, specified as one of the following:

  • "skip" – Skip empty columns.

  • "read" – Read empty columns.

  • "error" – Ignore empty columns during table detection and error when reading.

Example: "EmptyColumnRule","error"

Type for imported text data, specified as one of these values:

  • "string" — Import text data as string arrays.

  • "char" — Import text data as character vectors.

Example: "TextType","char"

Type for imported date and time data, specified as DatetimeType and one of these values: "datetime", "text", or "exceldatenum". The value "exceldatenum" is applicable only for spreadsheet files, and is not valid for text files.

ValueType for Imported Date and Time Data
"datetime"

MATLAB datetime data type

For more information, see datetime.

"text"

If "DatetimeType" is specified as "text", then the type for imported date and time data depends on the value specified in the "TextType" parameter:

  • If "TextType" is set to "char", then readtable returns dates as a cell array of character vectors.

  • If "TextType" is set to "string", then readtable returns dates as an array of strings.

"exceldatenum"

Excel serial date numbers

A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see Differences between the 1900 and the 1904 date system in Excel.

Example: "DatetimeType","datetime"

Flag to preserve variable names, specified as either "modify" or "preserve".

  • "modify" — Convert invalid variable names (as determined by the isvarname function) to valid MATLAB identifiers.

  • "preserve" — Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.

Starting in R2019b, variable names and row names can include any characters, including spaces and non-ASCII characters. Also, they can start with any characters, not just letters. Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname function). To preserve these variable names and row names, set the value of VariableNamingRule to "preserve". Variable names are not refreshed when the value of VariableNamingRule is changed from "modify" to "preserve".

Example: "VariableNamingRule","preserve"

Procedure to handle import errors, specified as one of the values in this table. An import error occurs when readtable is unable to convert text to the expected data type.

Import Error RuleBehavior
"fill"

Replace the data where the error occurred with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"error"Stop importing and display an error message showing the error-causing record and field.
"omitrow"Omit rows where errors occur.
"omitvar"Omit variables where errors occur.

Example: "ImportErrorRule","omitvar"

HTTP or HTTPS request options, specified as a weboptions object. The weboptions object determines how to import data when the specified filename is an internet URL containing the protocol type "http://" or "https://".

Index of table to read from Microsoft Word document or HTML file containing multiple tables, specified as a positive integer.

When you specify TableIndex, the software automatically sets TableSelector to the equivalent XPath expression.

Example: "TableIndex",2

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Procedure to handle cells with merged columns, specified as one of the values in this table.

Import Error RuleBehavior
"placeleft"

Place the data in the left-most cell and fill the remaining cells with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"placeright"

Place the data in the right-most cell and fill the remaining cells with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"duplicate"

Duplicate the data in all cells.

"omitrow"Omit rows where errors occur.
"error"Display an error message and abort the import operation.

Example: "MergedCellColumnRule","placeright"

Procedure to handle cells with merged rows, specified as one of the values in this table.

Import Error RuleBehavior
"placetop"

Place the data in the top cell and fill the remaining cells with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"placebottom"

Place the data in the bottom cell and fill the remaining cells with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"duplicate"

Duplicate the data in all cells.

"omitvar"Omit variables where merged rows occur.
"error"Display an error message and abort the import operation.

Example: "MergedCellRowRule","duplicate"

Row containing variable names, specified as a nonnegative integer.

  • If you do not specify VariableNamesRow, then the software reads variable names according to the ReadVariableNames argument.

  • If VariableNamesRow is 0, then the software does not import the variable names.

  • Otherwise, the software imports the variable names from the specified row.

Example: "VariableNamesRow",2

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Row containing variable units, specified as a nonnegative integer.

If VariableUnitsRow is 0, then the software does not import the variable units. Otherwise, the software imports the variable units from the specified row.

Example: "VariableUnitsRow",3

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Row containing variable descriptions, specified as a nonnegative integer.

If VariableDescriptionsRow is 0, then the software does not import the variable descriptions. Otherwise, the software imports the variable descriptions from the specified row.

Example: "VariableDescriptionsRow",4

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Table data XPath expression, specified as a character vector or string scalar that the reading function uses to select the output table data. You must specify TableSelector as a valid XPath version 1.0 expression. Use XPath selectors to specify which elements of the XML input document to import.

Selection OperationSyntax
Select every node whose name matches the node you want to select, regardless of its location in the document.Prefix the name with two forward slashes (//).
Select the value of an attribute belonging to an element node.Prefix the attribute with an at sign (@).
Select a specific node in a set of nodes.Provide the index of the node you want to select in square brackets ([]).
Specify precedence of operations.Add parentheses around the expression you want to evaluate first.

Example: "TableSelector","/RootNode/ChildNode"

Example: "myFile.xml", "TableSelector", "//table[1]"

HTML Files

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Type of file, specified as one of these values.

ValueFile Type
"spreadsheet"Spreadsheet files
"text"Text files
"delimitedtext"Delimited text files
"fixedwidth"Fixed-width text files
"xml"XML files
"worddocument"Microsoft Word document
"html"HTML files

Use the "FileType" name-value pair argument when filename does not include the file extension, or when the extension is not one of these:

  • .txt, .dat, or .csv for text files

  • .xls, .xlsb, .xlsm, .xlsx, .xltm, .xltx, or .ods for spreadsheet files

  • .xml, for XML files

  • .docx for Microsoft Word document files

  • .html, .xhtml, or .htm for HTML files

Example: "FileType","text"

Option to read the first column as row names, specified as a numeric or logical 1 (true) or 0 (false).

  • Set ReadRowNames to true when the first column of the region to read contains the row names for the table.

  • Set ReadRowNames to false when the first column of the region to read contains data, not the row names for the table.

If both the ReadVariableNames and ReadRowNames name-value arguments are true, then readtable saves the name in the first column of the first row of the region to read as the first dimension name in the property T.Properties.DimensionNames.

If you specify the ReadRowNames argument in addition to an import options object, then the readtable behavior changes based on the specification:

  • If ReadRowNames is true, then read the row names from the specified file by using the RowNamesColumn (DelimitedTextImportOptions, FixedWidthImportOptions), RowNamesRange (SpreadsheetImportOptions), or RowNamesSelector (XMLImportOptions) property of the respective import options object.

  • If ReadRowNames is false, then do not import row names.

If you use the import options syntax without specifying ReadRowNames, readtable uses the value associated with the import options object and its ReadRowNames name-value argument.

Example: "ReadRowNames",true

Placeholder text to treat as an empty value, specified as TreatAsMissing and a character vector, cell array of character vectors, string scalar, or string array. Table elements corresponding to these characters are set to NaN.

"TreatAsMissing" only applies to numeric columns in the table, and readtable does not accept numeric literals, such as "-99".

Example: "TreatAsMissing","N/A" or "TreatAsMissing","N/A" sets N/A within numeric columns to NaN.

Example: 'TreatAsMissing',{'.','NA','N/A'} or "TreatAsMissing",[".","NA","N/A"] sets ., NA and N/A within numeric columns to NaN.

Procedure to manage missing data, specified as one of the values in this table. Data is considered missing if an expected field in a row does not exist.

Missing RuleBehavior
"fill"

Replace missing data with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"error"Stop importing and display an error message showing the missing record and field.
"omitrow"Omit rows that contain missing data.
"omitvar"Omit variables that contain missing data.

Example: "MissingRule","omitrow"

Rule to apply to empty rows in the table, specified as one of the following:

  • "skip" – Skip empty rows.

  • "read" – Read empty rows.

  • "error" – Ignore empty rows during table detection and error when reading.

Example: "EmptyRowRule","read"

Rule to apply to empty columns in the table, specified as one of the following:

  • "skip" – Skip empty columns.

  • "read" – Read empty columns.

  • "error" – Ignore empty columns during table detection and error when reading.

Example: "EmptyColumnRule","error"

Type for imported text data, specified as one of these values:

  • "string" — Import text data as string arrays.

  • "char" — Import text data as character vectors.

Example: "TextType","char"

Type for imported date and time data, specified as DatetimeType and one of these values: "datetime", "text", or "exceldatenum". The value "exceldatenum" is applicable only for spreadsheet files, and is not valid for text files.

ValueType for Imported Date and Time Data
"datetime"

MATLAB datetime data type

For more information, see datetime.

"text"

If "DatetimeType" is specified as "text", then the type for imported date and time data depends on the value specified in the "TextType" parameter:

  • If "TextType" is set to "char", then readtable returns dates as a cell array of character vectors.

  • If "TextType" is set to "string", then readtable returns dates as an array of strings.

"exceldatenum"

Excel serial date numbers

A serial date number is a single number equal to the number of days from a given reference date. Excel serial date numbers use a different reference date than MATLAB serial date numbers. For more information on Excel dates, see Differences between the 1900 and the 1904 date system in Excel.

Example: "DatetimeType","datetime"

Flag to preserve variable names, specified as either "modify" or "preserve".

  • "modify" — Convert invalid variable names (as determined by the isvarname function) to valid MATLAB identifiers.

  • "preserve" — Preserve variable names that are not valid MATLAB identifiers such as variable names that include spaces and non-ASCII characters.

Starting in R2019b, variable names and row names can include any characters, including spaces and non-ASCII characters. Also, they can start with any characters, not just letters. Variable and row names do not have to be valid MATLAB identifiers (as determined by the isvarname function). To preserve these variable names and row names, set the value of VariableNamingRule to "preserve". Variable names are not refreshed when the value of VariableNamingRule is changed from "modify" to "preserve".

Example: "VariableNamingRule","preserve"

Procedure to handle import errors, specified as one of the values in this table. An import error occurs when readtable is unable to convert text to the expected data type.

Import Error RuleBehavior
"fill"

Replace the data where the error occurred with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"error"Stop importing and display an error message showing the error-causing record and field.
"omitrow"Omit rows where errors occur.
"omitvar"Omit variables where errors occur.

Example: "ImportErrorRule","omitvar"

HTTP or HTTPS request options, specified as a weboptions object. The weboptions object determines how to import data when the specified filename is an internet URL containing the protocol type "http://" or "https://".

Index of table to read from Microsoft Word document or HTML file containing multiple tables, specified as a positive integer.

When you specify TableIndex, the software automatically sets TableSelector to the equivalent XPath expression.

Example: "TableIndex",2

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Procedure to handle cells with merged columns, specified as one of the values in this table.

Import Error RuleBehavior
"placeleft"

Place the data in the left-most cell and fill the remaining cells with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"placeright"

Place the data in the right-most cell and fill the remaining cells with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"duplicate"

Duplicate the data in all cells.

"omitrow"Omit rows where errors occur.
"error"Display an error message and abort the import operation.

Example: "MergedCellColumnRule","placeright"

Procedure to handle cells with merged rows, specified as one of the values in this table.

Import Error RuleBehavior
"placetop"

Place the data in the top cell and fill the remaining cells with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"placebottom"

Place the data in the bottom cell and fill the remaining cells with the contents of the FillValue property.

The FillValue property is specified in the VariableImportOptions object of the variable being imported. For more information on accessing the FillValue property, see getvaropts.

"duplicate"

Duplicate the data in all cells.

"omitvar"Omit variables where merged rows occur.
"error"Display an error message and abort the import operation.

Example: "MergedCellRowRule","duplicate"

Row containing variable names, specified as a nonnegative integer.

  • If you do not specify VariableNamesRow, then the software reads variable names according to the ReadVariableNames argument.

  • If VariableNamesRow is 0, then the software does not import the variable names.

  • Otherwise, the software imports the variable names from the specified row.

Example: "VariableNamesRow",2

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Row containing variable units, specified as a nonnegative integer.

If VariableUnitsRow is 0, then the software does not import the variable units. Otherwise, the software imports the variable units from the specified row.

Example: "VariableUnitsRow",3

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Row containing variable descriptions, specified as a nonnegative integer.

If VariableDescriptionsRow is 0, then the software does not import the variable descriptions. Otherwise, the software imports the variable descriptions from the specified row.

Example: "VariableDescriptionsRow",4

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Table data XPath expression, specified as a character vector or string scalar that the reading function uses to select the output table data. You must specify TableSelector as a valid XPath version 1.0 expression. Use XPath selectors to specify which elements of the XML input document to import.

Selection OperationSyntax
Select every node whose name matches the node you want to select, regardless of its location in the document.Prefix the name with two forward slashes (//).
Select the value of an attribute belonging to an element node.Prefix the attribute with an at sign (@).
Select a specific node in a set of nodes.Provide the index of the node you want to select in square brackets ([]).
Specify precedence of operations.Add parentheses around the expression you want to evaluate first.

Example: "TableSelector","/RootNode/ChildNode"

Example: "myFile.xml", "TableSelector", "//table[1]"

Output Arguments

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Output table, returned as a table. The table can store metadata such as descriptions, variable units, variable names, and row names. For more information, see the Properties section of table.

Extended Capabilities

Version History

Introduced in R2013b

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See Also

Functions

Live Editor Tasks

Apps

Topics