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How to get rid of repeating values inside an array

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Rokki
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]

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Accepted Answer

José-Luis
José-Luis on 19 Sep 2017
Edited: José-Luis on 19 Sep 2017
b = a(sum(bsxfun(@eq,a,a'))==1)

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José-Luis
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.

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More Answers (1)

Andrei Bobrov
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]);

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Rokki
Rokki on 19 Sep 2017
Thank you for help. I am getting an error
Undefined function 'histcounts' for input arguments of type 'double'.
José-Luis
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.

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