Re: Check if a variable contains only one letter?

[toolic]

UPDATE: Nevermind... I misread the question. I thought the variable was of length 1. It would have helped had the OP shown any input at all.

Use eq instead of a regex:

use warnings;
use strict;

while (<DATA>) {
    chomp;
    print "ERROR $_\n" unless $_ eq 'X';
}

__DATA__
X
XA
XB

[LanX]

> It would have helped had the OP shown any input at all.

agreed, I also wasted time answering another question. :(

> Check if a variable contains only one letter

  DB<106> $str='A B C'
 => "A B C"

  DB<107> @matches= $str=~/([A-Z])/g
 => ("A", "B", "C")

  DB<108> scalar @matches
 => 3

  DB<115> $str='A B C'
 => "A B C"

  DB<116> $str !~ /[A-Z].*[A-Z]/
 => ""

  DB<117> $str="   A   "
 => "   A   "

  DB<118> $str !~ /[A-Z].*[A-Z]/
 => 1