Difference between two Vectors

I have two arrays
A = [-1 1 -2 1 -1 1 -1 -2 -1 1];
B = [-1 1 1 -1 1 -1 -1 1];
and i am wanting to find all of the values in A that do not appear in B.
So the answer would appear that
values = [-2 -2 ] % values that are in A but not B
index = [3 8] % location of 'values' in A
thanks

1 Comment

Further to my original question, i now need to find the difference between two vectors of different sizes , but the terms that are new will not be unique ie,
a = [-1 1 2 -2 1 -1 -2 -2 1 -1 -2 2 -1 1]
b = [-1 1 2 -2 1 -1 1 -1 -2 2 -1 1]
hence the difference between these two vectors are the two -2 terms at the centre of a .
The current code will only find new terms that have not appeared before but not the difference in the vectors.
Appreciate any help, thanks.

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 Accepted Answer

A = [-1 1 -2 1 -1 1 -1 -2 -1 1];
B = [-1 1 1 -1 1 -1 -1 1];
a=setdiff(A,B)
index=find(ismember(A,a))
values=A(index)

2 Comments

Thanks
Further to my original question, i now need to find the difference between two vectors of different sizes , but the terms that are new will not be unique ie,
a = [-1 1 2 -2 1 -1 -2 -2 1 -1 -2 2 -1 1] b = [-1 1 2 -2 1 -1 1 -1 -2 2 -1 1] hence the difference between these two vectors are the two -2 terms at the centre of a .
The current code will only find new terms that have not appeared before but not the difference in the vectors.
Appreciate any help, thanks.

Sign in to comment.

More Answers (1)

ii = ~ismember(A,B)
values = A(ii)
index = find(ii)

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Asked:

on 9 Nov 2013

Commented:

on 11 Nov 2013

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