eval alternative in Matlab reading from the workspace -

i'm reading matrix .mat file. alternative eval in case?

load([folder filename]); = eval(filename(1:end-4))*16 

i have heard eval slow...

if read mat file , contain matrix don't need eval statement:

mat = load([folder filename]); [a,matrixname,ext] = fileparts(filename);   = mat.(matrixname) * 16; 

please check contents of mat.