creating a matrix of zeros of size of another matrice

I have code , in which a matrice r as 1*100 matrice.

then It makes make

pp=zeros(1,size(r,2));

I don't know what 2 means , I know that 1 means the number of rows , but only 2 works in this comment

what is it ?

thank you

[per isakson]

Answer to the question in the subject line:

    B = zeros( size(A) );

and see the documentation on size.

Answer 1

[Mikhail]

So zeros(a1,a2) creates a matrix of zeros with a1 rows and a2 columns, for example:

    a=zeros(2,3)
is    
    a=0 0 0
      0 0 0

So code pp=zeros(1,size(r,2)); will create matrix pp with 1 row and size(r,2) columns. As long as size(r,2 ) is the number of columns of matrix r, size of pp will be equal to size of r.

Size(r,1) is number of rows in matrix r

Size(r,2) is number of columns

[farzad]

great thanks a lot