Q:

Concatenation: number to string in Matlab?

I have forgotten this: I need to concatenate numbers like '1'+'2'->'12'. I am trying to find a concatenate command String(var1)+String(var2). What is the concatenation command for Matlab?

A:

You need two things: convert the numbers to strings, then concatenate.  The solution is:
newString = [ num2str(var1) num2str(var2) ]

The result will be a string.

