in reply to isAlpha / isNumeric

There are a couple of problems with the code you have.

First, any white space or punctuation will be considered to be numeric - I somehow don't think that is what you want. This can be fixed by adding an elsif clause with a condition of $string =~ /^\d+$/. Of course, then you have to decide if white space and punctuation are valid inputs are not.

Second, consider the strings "a2" and "2a" - both will be considered Alphabet but your code. There is at least one character in each string thus the match succeeds. You want to anchor the match, something like $string =~ /^[a-zA-Z]+$/.

Third, are you sure that you want to use $a as a variable name. It has the same name as the built in sort variable and you did make it a my variable but to save yourself possible future bugs I would recommend against using $a (and $b) as temporary variables names.

The tests would probably look something like

if($string =~ /^[a-zA-Z]$/) # can also be written as /^[a-z]$/i { print "Alphabet\n"; } elsif($string =~ /^\d+$/) { print "Number\n"; } else { print "Other\n"; }
Depending on the source of the data you may also need to use chomp on the variable to get rid of any trailing newlines.

Edit: chipmunk 2001-03-22