Combining two arrays by pointwise repeating the elements of A(i), B(i) times.

I want to combine two vectors (A and B) with the same length into a new vector (C) with length sum of B.

e.g.

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

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

Thus repeating the elements of A, B times.

Answer 1

[Pierre Benoit]

You can use this function from the FEX : http://www.mathworks.com/matlabcentral/fileexchange/6436-rude-a-pedestrian-run-length-decoder-encoder/content/rude.m

Answer 2

[Matt J]

   idx(cumsum([1,B]))=ones(length(A)+1,1);
   C=A(cumsum(idx(1:end-1)))