Equality test not working?

Could someone please explain me this:

>> % uniqueness for the sets DOES NOT WORK! oh why?

iseq=isequal(unique([set01,set02]),[set01,set02])

diff=setdiff([set01,set02],unique([set01,set02]))

diff2=setdiff(unique([set01,set02]),[set01,set02])

--

iseq = 0

diff = Empty matrix: 1-by-0

diff2 = Empty matrix: 1-by-0

>>

Answer 1

[Andrew Newell]

The documentation says "c = setdiff(A, B) returns the values in A that are not in B. " The function unique extracts one copy of each element, so each element in [set01,set02] is also in unique([set01,set02]) and vice versa. The only difference is how many times they are repeated.

EDIT: This implements what you are trying to do:

s = [set01,set02];
[u, m] = unique(s);
notm = setdiff(1:length(s),m);
diff = s(notm)

Answer 2

[Jan]

The unique function sorts its input data. Therefore if "[set01, set02]" is unsorted, it does not equal "unique([set01, set02])", although both contain the same elements.

Try this:

iseq = isequal(unique([set01,set02]), sort([set01,set02]))

Another reason can be repeated elements in set01 and/or set02.

Answer 3

[Lauri]

Thank you.

Yes, I forgot to add that only for one set the uniqueness resulted true. So indeed it was the sorting I didn't count in.