Howto replace Element with Element from another Vector at the 1st Element's Position

Let's say I have a Vector with 100 integer Element between 1 & 100 in no particular Order.

A = [1:100];
A = (randperm (length(A)));

my 2nd Vector can be of any length and contains Integer Elements of any size. Let's Make it:

B = randi([1 200],1,250);

e.g. 250 Elements between 1 & 200 in no particular Order.

Elements of a Size beyond the Dimensions of Vector A don't interest me, so

B (B > 100) = NaN;

Here's what I wanna do:

To Replace all Integer Values in Vector B with the Value in Vector A at that Number's Position.

So let's say the First Element of B is 45. I want to replace it with the 45th Element in Vector A.

If the 2nd Element in B is 89, I want it replaced with the 89th Element in Vector A.

etc.

The NaNs just stay NaNs.

Answer 1

[Fangjun Jiang]

A=10:10:100;
B=[3,10,nan,2,nan];
index=~isnan(B);
B(index)=A(B(index))
B =

    30   100   NaN    20   NaN

[William Collants]

👌