Re-writing a loop including strcat in order to reduce computational time

I have the following loop:

   NameMatrix = []; 
   for i = 1:rows
       NameMatrix = [NameMatrix; {strcat(char(64+i),'1')} {strcat(char(64+i),'2')} {strcat(char(64+i),'3')} {strcat(char(64+i),'4')} {strcat(char(64+i),'5')}]; 
   end

Where rows is the number of rows of an input vector and changes size. With this I create rows x 5 cell which for rows = 3 looks like this:

    'A1'        'A2'  'A3'  'A4'  'A5'
    'B1'  'B2'  'B3'  'B4'  'B5'
    'C1'  'C2'  'C3'  'C4'  'C5'

If rows = 5 it would look like this:

    'A1'  'A2'  'A3'  'A4'  'A5'
    'B1'  'B2'  'B3'  'B4'  'B5'
    'C1'  'C2'  'C3'  'C4'  'C5'
    'D1'  'D2'  'D3'  'D4'  'D5'
    'E1'  'E2'  'E3'  'E4'  'E5'

I profiled my code and I noticed that the function strcat is super slow. How can I re-write the loop so that it produces the same output, but is faster?

Answer 1

[Azzi Abdelmalek]

n=5
m=10
s=regexp('A':'Z','\S','match');
out=genvarname(repmat(s(1:n)',1,m),s(1:n))