How can I convert an array to a matrix?

I have an array like B=[2 3 1 5 2 8 1 7 9 1 5 2 4 6 3 9 3 1 7 0 7 2 8 6].

I need this elements in a matrix called A like

A=

2 3 1 5 2 8 1 7

9 1 5 2 4 6 3 9

3 1 7 0 7 2 8 6

Please help...

Answer 1

[José-Luis]

 B=[2 3 1 5 2 8 1 7 9 10 5 21 4 6 3 9 3 1 7 0 7 2 8 6];
 A = reshape(B,8,3)'

Answer 2

[Andreas Goser]

In MATLAB all arrays are matrices... You may achieve what you need by using the RESHAPE command.

Answer 3

[Martin]

As Jose mentioned the reshape function is a really good one. The help file on that one is really useful for explaining how it works.