# Assigning values to vectors of different lenghts

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Christina on 27 Mar 2015
Answered: Jon on 27 Mar 2015
Hello,
I've got three vectors, say a(1x4), b(1x4) and c(1x10). Vectors a and c represent the same thing, they are just codes. Vector b let's say it's my objective function.
a = [1 2 3 4]
b = [0.1 0.2 0.3 0.4]
c= [ 4 4 4 2 2 1 3 3 1 4].
I want to get another vector d, which will have the same dimensions as vector d (10x1) and in which the values of vector b will be assigned.
d should be like d = [0.4 0.4 0.4 0.2 0.2 0.1 0.3 0.3 0.1 0.4].
Any thoughts on this?
Many thanks

Konstantinos Sofos on 27 Mar 2015
Edited: Konstantinos Sofos on 27 Mar 2015
Hi,
if your starting point is that you have a and c you can make d from b as
[~,idx] = ismember(c,a);
d = b(idx);
>> d
d =
0.4000 0.4000 0.4000 0.2000 0.2000 0.1000 0.3000 0.3000 0.1000 0.4000
Christina on 27 Mar 2015
Good, it works!
Many thanks!

Jon on 27 Mar 2015
It's not clear what you need a for. You can make d directly from c and b as follows:
>> d=b(c)
d =
0.4 0.4 0.4 0.2 0.2 0.1
0.3 0.3 0.1 0.4