Convert cell to matrix

I have the following {'128' '256' '157' '54'} How can I convert it to a numeric matrix for example 128 256 157 54

[Martin Park]

I mean

 128 256
 157 54

Answer 1

[Walter Roberson]

str2double()

Answer 2

[Jan]

Faster than str2double:

C = {'128' '256' '157' '54'};
S = sprintf('%s*', C{:});
D = sscanf(S, '%g*');