MATLAB: Converting cell array to double

cell arrays

How can I convert the cell array A into the column vector B? (Deleting the letter B and leading white spaces)

A = { 'B 1'; 'B 12'; 'B123' }

B = [ 1; 12; 123 ]

A = { 'B 1'; 'B 12'; 'B123' }
B=str2double(regexp(A,'\d+','match','once'))

B{1} = A

It's pretty easy really. Here an example:

A = {rand([2 1]),rand([5 1]),rand([3 1])};
B = {rand([10 1]),rand([12 1])};
C = [A B]; %adds cell B to A