Question

I have a matrix with one column like this:

NNN

NNN

NNN

AAA

AAA

CCC

CCC

DDD

DDD

DDD

I would like to remove all the lines in which I don’t have 3 repetitions. This would result in removing lines 4,5,6,7 (and the result would be only the matrix with the remaining:

NNN

NNN

NNN

DDD

DDD

DDD

(PS: Those are strings, not numbers).

Is there an inteligent way to do that using matlab? I mean, using the functions and etc? Because I solved the problem with a for, but I think it is not the best way to do it and that it must have another way.

Thanks for the help in advance! 🙂

Answer 1

This should do it:

t=tabulate(x) % count how much each element appears
valid=t(cell2mat(t(:,2))>=3,1) % find strings that appear at least 3 times 
result=x(ismember(x,valid)) % select only these strings

I assume here that x is a cell matrix with one column of strings. If x has other columns it is an easy fix.