Searching text of one file in another file by matlab

Question

What i have is 2 column vector variables/files each containing text entries. Lets say one is mx1 and other is nx1 (n>m). And the entries present in first file is present in second file but can be multiple times. So i want all those index, of second file at which the entries matches with first file. Example:

first file contains [ am pm cm dm]' and second file contains [am am bm pm pm pm dm em cm]'

So the answer will return as [1 2 4 5 6 7 9]'

Please help.

OR

If it can make a third file having only common entries like [am am pm pm pm dm cm]

Answer 1

Just use ismember:

1. Assuming your strings are contained in cell arrays:

   >> cell1 = {'am' 'pm' 'cm' 'dm'};
   cell2 = {'am' 'am' 'bm' 'pm' 'pm' 'pm' 'dm' 'em' 'cm'};
   find(ismember(cell2,cell1))
   
   ans =
   
        1
        2
        4
        5
        6
        7
        9
   

2. If your strings are all equal-length and are defined as rows of text matrices:

   >> matrix1 = ['am';'pm';'cm';'dm'];
   matrix2 = ['am';'am';'bm';'pm';'pm';'pm';'dm';'em';'cm'];
   find(ismember(matrix2,matrix1,'rows'))
   
   ans =
   
        1
        2
        4
        5
        6
        7
        9