Is it possible to scan a group of lines in MATLAB?

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I have a textfile I would like to pull data from. Rather than reading line by line I would like to just have it scan my textfile in chunks. For example scanning it every 10 lines. Then I intend to write some of the data from these 10 lines to a new file and read the next 10 lines. Is this possible?

Accepted Answer

Jan
Jan on 12 Sep 2013
I do not see the general difference between scanning a file line by line or in blocks of 10 lines.
fid = fopen(FileName, 'r');
if fid == -1, error('Cannot open file: %s', FileName);
k = 0;
C = {};
D = cell(1, 10);
proceed = true;
while 1
for m = 1:10
s = fgetl(fid);
if ~ischar(s)
proceed = false;
D = D(1:m);
break;
end
D{m} = s;
end
k = k + 1;
C{k} = D;
end
Instead of storing D in C, you can parse it how ever you like.
This wooden technique is efficient, when you do not have to keep all lines in the memory at once (omit everything concerning "C" then). textscan looks much nicer, but is not necessarily faster.

More Answers (2)

Walter Roberson
Walter Roberson on 11 Sep 2013
Yes. After the format specifier, in the next parameter put the number of times you want the format to be reused. 10 for example if the format is for one line's worth of information.

sanky kumar
sanky kumar on 11 Sep 2013
hi brian
you can use textscan.
C = textscan(fileID,formatSpec) reads data from an open text file into cell array, C. The text file is indicated by the file identifier, fileID. Use fopen to open the file and obtain the fileID value. When you finish reading from a file, close the file by calling fclose(fileID).
textscan attempts to match the data in the file to formatSpec, which is a string of conversion specifiers.
  1 Comment
Brian
Brian on 11 Sep 2013
So for example, would I put
textscan('example.txt',10);
and if I wanted to read specific data on the line I would add %f after 10?
textscan('example.txt',10,%f)

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