# How to get rid of repeating values inside an array

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Rokki on 19 Sep 2017
Edited: Andrei Bobrov on 21 Sep 2017
I have a matrix
a=[1 2 3 3 4 4 5];
I want to get rid of values 3 and 4 as they are repeating so that the output becomes
b=[1 2 5]

José-Luis on 19 Sep 2017
Edited: José-Luis on 19 Sep 2017
b = a(sum(bsxfun(@eq,a,a'))==1)
##### 2 CommentsShow NoneHide None
Rokki on 19 Sep 2017
Thank you very much
José-Luis on 19 Sep 2017
Edited: José-Luis on 19 Sep 2017
My pleasure.
Please keep in mind that this is inefficient for large arrays though. Just using unique() should take you where you need to go.

### More Answers (1)

Andrei Bobrov on 19 Sep 2017
Edited: Andrei Bobrov on 21 Sep 2017
v = unique(a);
b = v(histcounts(a,[v(:);v(end)+eps]) == 1);
or
v = unique(a);
b = v(histc(a,v) == 1);
or
aa = sort(a);
t = diff(aa);
b = aa([1 t] & [t 1]);
##### 3 CommentsShow 1 older commentHide 1 older comment
José-Luis on 19 Sep 2017
histcounts() was introduced with R2014b. You don't need it though. unique() is enough. Andrei was giving you two alternatives.
Andrei Bobrov on 19 Sep 2017
fixed