X = getnext(ValIter) returns
the next available value in ValIter. Use the hasnext function
to confirm availability of values in ValIter before
calling getnext.
Use the hasnext and getnext functions
in a while loop within the reduce function to iteratively
get values from the ValueIterator object. For example,
function MeanDistReduceFun(sumLenKey, sumLenIter, outKVStore)
sumLen = [0 0];
while hasnext(sumLenIter)
sumLen = sumLen + getnext(sumLenIter);
end
add(outKVStore, 'Mean', sumLen(1)/sumLen(2));
end
Always call hasnext before getnext to
confirm availability of a value. mapreduce returns
an error if you call getnext with no remaining
values in the ValueIterator object.
ValIter — Intermediate value iterator ValueIterator object
Intermediate value iterator, specified as a ValueIterator object.
The mapreduce function automatically creates
this object during execution. The second input to the reduce function
specifies the variable name for the ValueIterator object,
which is the variable name to use with the hasnext and getnext functions.