Find same numbers in two vectors

Hello,

i need to find same numbers in two vectors and write them down in a third one. Example:

a = [3,8,10,11]
b = [2,3,10,12]

The result should be this vector:

result = [3,10]

Do you have an idea how to do this?

Thanks

Robert

Answer 1

[Johannes Fischer]

I think what you need is the ismember function:

a = [3,8,10,11]
b = [2,3,10,12]

result = a(ismember(a, b))
% or
result = b(ismember(b, a))

[Robert Schumann]

Thank you very much!!

[Johannes Fischer]

Keep in mind that the results will be different, when a number occurr multiple times

a = [3,8,10,11,3];
b = [2,3,10,10,12];

resultA = a(ismember(a, b))
resultB = b(ismember(b, a))

leads to

resultA =

     3    10     3
resultB =

     3    10    10     

You can avoid this using unique:

resultA = unique(a(ismember(a, b)))
resultB = unique(b(ismember(b, a)))

will lead to

resultA =

     3    10
resultB =

     3    10