Replace some values of a vector with another vector which has a different size

Hello

I've got the vector: source = [ 0 0 1 0 1]

and the vector a = [2 3],

which has a different size to source.

I'd like to replace in the source vector the elements that are equal to 1, with those of vector a.

The final vector b should be: b = [0 0 2 0 3]

Any thoughts on this?

Thank you!

Answer 1

[Thorsten]

 source(source == 1) = a

[Christina]

Thank you! It works!

[pfb]

However, that changes "source" instead of creating "b", as asked in the question.

Answer 2

[pfb]

 b=zeros(size(source));
 b(find(source))=a;

of course this works only if the number of nonzero elements in source are the same as the elements in a.

[Christina]

Thank you! It works

Answer 3

[Stephen23]

This can be achieved very simply using basic logical indexing:

>> A = [ 0 0 1 0 1];
>> B = [ 2 3];
>> A(A==1) = B
A = 0  0  2  0  3

On my computer this was almost twice as fast compared to using find and zeros.

[Christina]

Hey Stephen,

Are you sure you haven't omitted anything, because this cannot work..

[James Tursa]

Stephen switched nomenclature. His starting "A" is your "source" his "B" is your "a", and his resulting "A" is your "b".

[Stephen23]

Guilty as charged.