finding only unique values

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Bernard
Bernard on 22 Aug 2013
Suppose you have a column vector, the values are integers(in order) but some of them are repeated, e.g. it could be [1,1,1,1,2,3,3,4,5,5,5,5,5] I want to find the indices of unique values e.g. the index of 2 and 4 in the aforementioned example. the unique function in matlab returns on top of truly unique the first value of any nonunique value, so it would return the index of the first 1, the first 3 and first 5 but I don't want those

Accepted Answer

the cyclist
the cyclist on 22 Aug 2013
Edited: the cyclist on 22 Aug 2013
Maybe call these the "singleton" values. Here's one way:
x = [1,1,1,1,2,3,3,4,5,5,5,5,5];
unique_x = unique(x);
count_x = hist(x,unique_x);
singleton_x = unique_x(count_x==1)
  1 Comment
Bernard
Bernard on 22 Aug 2013
brilliant this saved me time thanks

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More Answers (2)

David Sanchez
David Sanchez on 22 Aug 2013
a=[1,1,1,1,2,3,3,4,5,5,5,5,5];
x = unique(a)
y = histc(a,x)==1;
lonely_values = find ( y == 1 )
or:
lonely_values = find ( (histc(a,unique(a))==1) == 1 )
lonely_values =
2 4

Azzi Abdelmalek
Azzi Abdelmalek on 22 Aug 2013
[ii,jj]=sort(x);
out=sort(jj(strfind(logical([1 diff(ii) 1]),[true,true])))

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