how to extract element from column vectors

I have

P1= (x1; x2; x3...upto x80), similarly 
P2= (y1; y2;.. upto y80), and so on .....upto P31 column vector.

Each contains 80 elements. I want 80 column vectors (A1, A2...upto A80) such that,

A1 = (x1; y1;.......) (consist of 31 elements)
A2 = (x2; y2; ......) (consist of 31 elements)

how to do that?

Answer 1

[Adam]

Is it not possible to have your original data just stored in a single 31 by 80 matrix?

With so many individually named variables you really don't have many options outwith using eval which is not generally advised.

Answer 2

[dpb]

Don't do that!!! For why not and alternatives see the FAQ

http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F