Re: how to check whether a particular word exists in filename

[Preceptor]

Edited, because it's wrong.

[ww]

"...but not 'CHECK_ABC123_A1.txt' "

Nope! Not true.

C:\>perl -E "my $s='CHECK_ABC123_A1.txt';say $s if ($s =~ m/^CHECK_(\w
++)\.txt/ );"
CHECK_ABC123_A1.txt

or, alternately,

#!/usr/bin/perl
use 5.016;
use strict;
use warnings;

# 1042260

my $s='CHECK_ABC123_A1.txt';
if ( $s =~ m/^CHECK_(\w+)\.txt/ ) {
    say "\t \$1 is: $1\n\t and the regex matched the source string.";
} else {
    say "\t Nope. Regex didn't match \$s.";
}

=head OUTPUT:


         $1 is: ABC123_A1
         and the regex matched the source string.

=cut

Pls test your advice... (unless you were trying to get a clueless OP to turn in homework with an error).

[Happy-the-monk]

Nope! Not true.

That is because in the character class [A-Za-z0-9] there is no underscore, and Preceptor assumed that would be equivalent to \w .
\w , however, is [A-Za-z0-9_] and thus includes the underscore.

Cheers, Sören