Making a matrix of strings read in from file using feof function in matlab - matlab

Question

I have an index file (called runnumber_odour.txt) that looks like this:
run00001.txt ptol
run00002.txt cdeg
run00003.txt adef
run00004.txt adfg
I need some way of loading this in to a matrix in matlab, such that I can search through the second column to find one of those strings, load the corresponding file and do some data analysis with it. (i.e. if I search for "ptol", it should load run00001.txt and analyse the data in that file).
I've tried this:
clear; clc ;
% load index file - runnumber_odour.txt
runnumber_odour = fopen('Runnumber_odour.txt','r');
count = 1;
lines2skip = 0;
while ~feof(runnumber_odour)
runnumber_odourmat = zeros(817,2);
if count <= lines2skip
count = count+1;
[~] = fgets(runnumber_odour); % throw away unwanted line
continue;
else
line = strcat(fgets(runnumber_odour));
runnumber_odourmat = [runnumber_odourmat ;cell2mat(textscan(line, '%f')).'];
count = count +1;
end
end
runnumber_odourmat
But that just produces a 817 by 2 matrix of zeros (i.e. not writing to the matrix), but without the line runnumber_odourmat = zeros(817,2); I get the error "undefined function or variable 'runnumber_odourmat'.
I have also tried this with strtrim instead of strcat but that also doesn't work, with the same problem.
So, how do I load that file in to a matrix in matlab?

Answer 1

You can do all of this pretty easily using a Map object so you will not have to do any searching or anything like that. Your second column will be a key to the first column. The code will be as follows
clc; close all; clear all;
fid = fopen('fileList.txt','r'); %# open file for reading
count = 1;
content = {};
lines2skip = 0;
fileMap = containers.Map();
while ~feof(fid)
if count <= lines2skip
count = count+1;
[~] = fgets(fid); % throw away unwanted line
else
line = strtrim(fgets(fid));
parts = regexp(line,' ','split');
if numel(parts) >= 2
fileMap(parts{2}) = parts{1};
end
count = count +1;
end
end
fclose(fid);
fileName = fileMap('ptol')
% do what you need to do with this filename
This will provide for quick access to any element
You can then do what was described in the previous question you had asked, with the answer I provided.