find number of columns on text file
11 views (last 30 days)
Show older comments
Is it possible to determine the number of columns in a text file prior to importing the data into matlab?
I can determine the number of rows as follows:
fid = fopen('myFile.txt','rt');
nLines = 0;
while (fgets(fid) ~= -1),
nLines = nLines+1;
end
fclose(fid);
However, is there a way of returning the number of columns? Some of the text files that I need to import contain several column and others contain only one column therefore I require the number of columns in a specific text file in order to use textscan. Note I cannot use importdata or dlmread as some of the files contain nans.
Amended: Consider I create two text files:
d1 = 1+(30-1).*rand(365,3);
d2 = 1+(30-1).*rand(365,1);
mkdir('C:\Matlab_Q');
filename = 'C:\Matlab_Q\ex1.txt';
fid = fopen(filename,'wt');
fprintf(fid,'%f\n',d2);
fclose(fid);
filename = 'C:\Matlab_Q\ex2.txt';
fid = fopen(filename,'wt');
fprintf(fid,'%f\t%f\t%f\n',d1');
fclose(fid);
I now wish to read the number of columns in each text file:
FNames = {'ex1','ex2'};
delimiter = '\t';
for i = 1:length(FNames);
fid = fopen(fullfile('C:\Matlab_Q',[FNames{i} '.txt']),'rt');
tLines = fgets(fid);
numCols{i} = numel(strfind(tLines,delimiter)) + 1;
fclose(fid);
end
This solution returns 1 where it should return 1 and 3. How can this be solved?
0 Comments
Accepted Answer
José-Luis
on 20 Nov 2012
Edited: José-Luis
on 20 Nov 2012
delimiter = ' '; %or whatever
fid = fopen('myFile.txt','rt');
tLines = fgets(fid);
numCols = numel(strfind(tLines,delimiter)) + 1;
fclose(fid);
3 Comments
Mitchell Thayer
on 7 Jan 2013
Snagged that piece of code for use in a parsing function. Thanks!
-:- Mitchell
More Answers (0)
See Also
Categories
Find more on Text Files in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!