Why does setdiff answer depend on order of arguments?
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>>bob = {'a','b','c'};
>>bill = {'a','b','c', 'd','e'}
As expected,
>>A = setdiff(bill,bob)
A =
'd' 'e'
BUT
>> B = setdiff(bob,bill)
B =
Empty cell array: 1-by-0
WHY??
0 Comments
Accepted Answer
Steven Lord
on 9 Sep 2019
Were you expecting the output to contain elements that are only in one of the inputs but not both? That's not what setdiff does. If that is what you want to do, use setxor instead.
2 Comments
Stephen23
on 10 Sep 2019
Edited: Stephen23
on 10 Sep 2019
It is worth nothing that MATLAB setdiff follows the standard mathematical definition of "set difference", which is defined as A\B (i.e the elements of A that are not in B):
etc.
Although this is the accepted mathematical definition, the term "set difference" is rather ambiguous in common english. It would be nice if it used terms whose meaning was obvious.
More Answers (2)
madhan ravi
on 9 Sep 2019
Edited: madhan ravi
on 9 Sep 2019
bob not in bill (nothing unique all elements of bob belong to bill)
help setdiff
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