readData() function error message when using mapreduce

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I have a very large file (100's of millions of data points) and I am using mapreduce and datastore to get access to specifc chunks of data.
I get the following error (below) when I run it and I do not know how to go around it. lAny suggestions on how to deal with this?
Error using (line 81)
Mismatch between file and format character vector.
Trouble reading 'Numeric' field from file (row number 1136, field number 15) ==>
Error in (line 120)
[t, info] = readData(ds);
Error in (line 7)
[varargout{1 : nargout}] = read(ds);
Error in mapreduce (line 116)
outds = execMapReduce(mrcer, ds, mapfun, reducefun, parsedStruct);
Caused by:
Reading the variable name 'ticker' using format '%f' from file

Accepted Answer

Jeremy Hughes
Jeremy Hughes on 5 Aug 2019
ds.TextscanFormats{15} = '%q'
That will at least get you past the one line that's causing the problem here. For a more robust answer, I'd have to look at the file. It could be that there's an error in a line somewhere that's throwing off the parsing.

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