If a=[1 2 3], b=[10 20 30], how to create c=[10 20 20 30 30 30]?

The b matrix i'th element is repeated the number of times the given number in 'a' matrix and placed in matix 'c'. Also if a=[0 1 2], b=[10 20 30] how to get c=[20 30 30]??

Answer 1

[Alfonso Nieto-Castanon]

 c = cell2mat(arrayfun(@repmat,b,ones(size(a)),a,'uni',0));

[Joshua]

Thank you :)

[Jan]

Very nice: +1

Answer 2

[Roger Stafford]

Another way:

 t = accumarray(cumsum([1,a]).',1);
 c = b(cumsum(t(1:end-1)));

[Jan]

I assume you mean "t = " instead of "t - "

[Roger Stafford]

Oops! Yes, thank you Jan.

Answer 3

[Jan]

For large array this is efficient: FEX: RunLength

c = RunLength(a, b)