How to replace and delete specific lines of a .txt file?

Hello,

I have a question about a code. I have two .txt files with 15 columns (let's call them fileA.txt & fileB.txt). I would like to delete the rows (lines) from fileB.txt whose columns 3,4,6 are contained (are the same) in fileA.txt.

I mean that

fileA.txt contains:

5 6 7 8 10 Italy 18 22

4 3 2 1 5 Rome 22 38

11 26 17 1 93 Spain 40 85

and fileB.txt contains:

4 3 7 8 6 Italy 26 12

7 9 2 1 7 Rome 36 85

25 12 94 6 8 Turkey 23 78

after this process I would like to have these modifications:

fileA.txt

4 3 7 8 6 Italy 26 12

7 9 2 1 7 Rome 36 85

11 26 17 1 93 Spain 40 85

fileB.txt

25 12 94 6 8 Turkey 23 78

I think I should use commands isequal & ismember but I am condused. I am uploading the files..

Could you please help me?

Answer 1

[Atsushi Ueno]

ismember function works for your purpose.

fileA = readtable('https://jp.mathworks.com/matlabcentral/answers/uploaded_files/1342194/fileA.txt');
fileB = readtable('https://jp.mathworks.com/matlabcentral/answers/uploaded_files/1342199/fileB.txt');
result = ismember(fileB(:,[3 4 6]),fileA(:,[3 4 6]),'rows');
fileA(result,:) = fileB(result,:);
fileB(result,:) = [];
writetable(fileA,'fileA.txt','Delimiter','\t','WriteVariableNames',false);
writetable(fileB,'fileB.txt','Delimiter','\t','WriteVariableNames',false);
type fileA.txt

4	3	7	8	6	Italy	26	12
7	9	2	1	7	Rome	36	85
11	26	17	1	93	Spain	40	85

type fileB.txt

25	12	94	6	8	Turkey	23	78