Simple vector question.

Say that I have the vectors

v1=[1 2 3]
v2=[4 3 8]

how can I, by using these two, create the following vector

v3=[4 3 3 8 8 8]

i.e., a vector with one 4s, two 3s and three 8s.

Answer 1

[David Hill]

v=repelem(v2,v1);

[Sebastian Daneli]

Thanks, a follow-up question, I have this matrix

X=[9 6 9; 0 2 nan; 3 1 2];

How can I easly find the number of elements of each row? I.e., get the vector

v=[3;2;3]

[David Hill]

sum(~isnan(X),2)

[Sebastian Daneli]

Great, thanks.