textscan in a for loop, memory issue

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Orion
Orion 2015-7-6
回答： Chris Eguires 2017-6-21
I have a text file with 140000 lines, each line has a string at the beginning and then 10 data points. I want to read this file 500 lines at a time and do some calculations based on the string data. So I have a for loop:
for t=1:280
clearvars dataArray
startRow = 1+500*(t-1);
endRow = (500-1) + startRow;
% Open the text file.
dataArray = textscan(fileID, formatSpec, endRow-startRow+1,...
'Delimiter', delimiter, 'HeaderLines', startRow-1,...
'ReturnOnError', false);
x=dataArray{:,3:5};
y=dataArray{:,6:9};
...
...
...
end
the problem is after iteration t=25, textscan doesn't read any data and it returns empty arrays. if I change the for loop to start from 10:
for t=10:280
...
...
end
the error occurs at t=28. It seems to me that there is a memory issue. Is there any way to check what is causing this problem?

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回答（2 个）

Harsha Medikonda
Harsha Medikonda 2015-7-8
I understand that you wish to know if the behavior you are observing is related to Memory. Please execute the command 'memory' before and after executing the code. This command shows the amount of memory available.
Please refer to the link below for more details on the usage of 'memory' http://www.mathworks.com/help/matlab/ref/memory.html
Another alternative to access large files is using 'datastore'. Please refer to the following link for more details on its usage http://www.mathworks.com/help/matlab/ref/datastore.html
Chris Eguires
Chris Eguires 2017-6-21
You need to do the following after you do the read; fseek(fileID,0,'bof');

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