Matlab或R：用另一个矩阵中的值依次替换矩阵中的元素

Question

I have a problem to solve in either Matlab or R (preferably in R).

Imagine I have a vector A with 10 elements.

I have also a vector B with 30 elements, of which 10 have value 'x'.

Now, I want to replace all the 'x' in B by the corresponding values taken from A, in the order that is established in A . Once a value in A is taken, the next one is ready to be used when the next 'x' in B is found.

Note that the sizes of A and B are different, it's the number of 'x' cells that coincides with the size of A.

I have tried different ways to do it. Any suggestion on how to program this?

Answer 1

As long as the number of x entries in B matches the length of A , this will do what you want:

B[B=='x'] <- A

(It should be clear that this is the R solution.)

Answer 2

MATLAB Solution

In MATLAB it's quite simple, use logical indexing:

B(B == 'x') = A;