How to repeat an array based on another array

Greetings

I am trying to repeat an array based on another array e.g

Repeat element of array A based on the elements of array B

A= [ 1 2 3 4 ] 
B= [ 2 3 1 2]

the resulted array should be ( first element of A that is 1 repeated 2 times which is the first element of array B and so on )

C= [ 1 1 2 2 2 3 4 4 ]

Answer 1

[the cyclist]

Use repelem.

C = repelem(A,B)

[Mohammed Alshehri]

Thank you. It worked.

Answer 2

[Stephen23]

For MATLAB before R2015a:

>> A = [1,2,3,4];
>> B = [2,3,1,2];
>> cell2mat(arrayfun(@(a,b)repmat(a,1,b),A,B,'uni',0))
ans =
     1     1     2     2     2     3     4     4