Writing data to excel files, MATLAB - excel

Question

I am using MatlabR2011a on my Windows 7 machine.
I have a folder of 635 text files. Each file contains multiple rows and 2 columns. I am trying to loop through the folder and read each file and write these values to excel. So far this is what I have:
close all; clc;
dirname = uigetdir;
Files = dir(fullfile(dirname,'*.txt'))
for k = 1:635
j =1
filename = fullfile(dirname,Files(k).name);
fid = fopen(filename);
x = fgetl(fid)
while ischar(x)
x = fgetl(fid)
a2 = strtrim(x);
a3 = textscan(a2,'%s');
a4 = a3{1}{1};
a5= a3{1}{2};
pos3 = strcat('A',num2str(j));
xlswrite('sample_output',{a4,a5},'Sheet1',pos3)
j = j+1;
end
fclose(fid);
end
It keeps giving me the following error after finishing reading the first file.
Error using ==> strtrim Input should be a string or a cell array of strings.
A sample input file looks like this:
15076 4636259
15707 4636299
15714 1781552
15721 4204950
15730 2174919
16209 4636510
16413 4758572
16470 4445808
17519 311397
17667 2116489
17739 1729694
18024 3210756
18627 3714194
18695 4192858
19141 632766
19318 1923574
19438 1255216
19493 4635020
19771 4770250
How can I fix this? Would appreciate help with this!

Answer 1

In the while loop, cut the line
x=fgetl(fid)
...and paste it before the end statement right after j=j+1.
The error occurs because you get a line before the while statement, then you use the while statement to test validity of the string (all fine so far), but then immediately get the subsequent line before you perform your string operation. The call to fgetl at the start of the while block could return an EOF, causing subsequent string manipulation functions to fail.
Also... The code would be more robust if you set your for loop like so
for k=1:numel(Files)

Answer 2

Since all your data are numeric this should work. Give it a try.
dirname = uigetdir;
Files = dir(fullfile(dirname,'*.txt'))
j =0;
for k = 1:numel(Files)
filename = fullfile(dirname,Files(k).name);
x = dlmread(filename,'\t'); %# I assume tab-delimiter
j = j + size(x, 1);
xlswrite( 'sample_output', x, 'Sheet1',sprintf('A%d',j) )
end