Find values in list that appear exactly once

Hi there,

assume, i have a list of integer values. I need a fast way to find those values in the list, that appear exactly once.

By now i have a code that finds the duplicate values and dismisses them.

    list = randi(100,100,1);   % Generate a list which should contain duplicate values
    [vals,i]=sort(list);
    j=find(all(diff(vals)==0,2));
    ii=i([j;j+1]);
    list(ii)=[];

Is there a faster way to get the final result?

Cheers, Johannes

Answer 1

[Stephen23]

How about this:

[tmp,idx] = sort(list);
idp = diff(tmp)>0;
list(idx([true;idp]&[idp;true]))

If you are okay with getting the output sorted then it can be simplified further:

tmp = sort(list);
idp = diff(tmp)>0;
tmp([true;idp]&[idp;true])

[Johannes Korsawe]

Congrats! Thats average 36% faster than my previous code!

Thank you.

[Mohammadreza Mahmoodi]

what is idp means ?

[Stephen23]

@Mohammadreza Mahmoodi: idp is a logical vector which indicates where the values change.