Comparing two files of dissimilar sizes

I have following two files:

File 1.

0.291851
0.495348
1.162611
-0.495348
-0.203497
0.667262
-0.291851
0.203497
0.870759
-1.761256
-1.469404
-1.265908
-1.162611
-0.870759
-0.667262

File 2.

1       2.000000        4.953483e-01
1       3.000000        2.918515e-01
1       4.000000        1.761256e+00
1       5.000000        1.162611e+00
2       1.000000        -4.953483e-01
2       3.000000        -2.034968e-01
2       4.000000        1.265908e+00
2       5.000000        6.672624e-01
3       1.000000        -2.918515e-01
3       2.000000        2.034968e-01
3       4.000000        1.469404e+00
3       5.000000        8.707592e-01
4       1.000000        -1.761256e+00
4       2.000000        -1.265908e+00
4       3.000000        -1.469404e+00
4       5.000000        -5.986453e-01
5       1.000000        -1.162611e+00
5       2.000000        -6.672624e-01
5       3.000000        -8.707592e-01
5       4.000000        5.986453e-01

File 1 is single column file consisting of 15 rows and File 2 consists of 20 rows and 3 columns. I want to compare each element of file 1 with file 2 and copy whole row matching the element in file 2 in third output file. Any help would be appreciated. Thanks in Advance.

Answer 1

[Guillaume]

file1 = dlmread('c:\somewhere\file1.txt');
file2 = dlmread('c:\somewhere\file2.txt');
tokeep = ismember(file2(:, 3), file1);
dlmwrite('c:\somewhere\file3.txt', file2(tokeep, :), '\t');

You may need to use ismembertol instead of ismember if the values in both files are not exactly equal.

[Abhinav Srivastava]

Following your advice, I tried the following:

file1 = dlmread('min_dist.txt');
file2 = dlmread('sorted_file.txt');
tokeep = ismember(sorted_file.txt(:, 3), min_dist.txt);
dlmwrite('output.txt', sorted_file.txt(tokeep, :), '\t');

It generates an error message: Undefined variable "sorted_file" or class "sorted_file.txt".

[Abhinav Srivastava]

I have the two input files named as : min_dist.txt and sorted_file.txt. The content of file min_dist.txt is 1.0000 2.0000 0.4953 1.0000 3.0000 0.2919 1.0000 4.0000 1.7613 1.0000 5.0000 1.1626 2.0000 1.0000 -0.4953 2.0000 3.0000 -0.2035 2.0000 4.0000 1.2659 2.0000 5.0000 0.6673 3.0000 1.0000 -0.2919 3.0000 2.0000 0.2035 3.0000 4.0000 1.4694 3.0000 5.0000 0.8708 4.0000 1.0000 -1.7613 4.0000 2.0000 -1.2659 4.0000 3.0000 -1.4694 4.0000 5.0000 -0.5986 5.0000 1.0000 -1.1626 5.0000 2.0000 -0.6673 5.0000 3.0000 -0.8708 5.0000 4.0000 0.5986 and content of file sorted_file.txt is 0.2919 0.4953 1.1626 -0.4953 -0.2035 0.6673 -0.2919 0.2035 0.8708 -1.7613 -1.4694 -1.2659 -1.1626 -0.8708 -0.6673 I am trying to compare elements from file sort_dist.txt with min_dist.txt and then copy lines from min_dist.txt to output. Following is my code: b = load('min_dist.txt') a = load('sorted_file.txt')

   for i= 1: length (a)
       for j= 1:length(b)

          if j >= i
              if a(i,1)==b(j,3)
                  disp(b(j,:))
              end
          end
       end      
   end
When I am running the code, it gives the following output
 1.0000    5.0000    1.1626

    4.0000    1.0000   -1.7613

    4.0000    3.0000   -1.4694

    4.0000    2.0000   -1.2659

    5.0000    1.0000   -1.1626
Kindly help me regarding the same. 
Thanks in advance

[Guillaume]

Using your file names, the code should be:

file1 = dlmread('min_dist.txt');
file2 = dlmread('sorted_file.txt');
tokeep = ismember(file2(:, 3), file1);
dlmwrite('c:\somewhere\file3.txt', file2(tokeep, :), '\t');