Re: Removing unwanted chars from filename.

[hippo]

If you are stripping out all characters from a known set then tr is the way to go for 2 reasons. Firstly, it's lightning fast. Secondly you cannot accidentally construct a pattern of more than a single character. Here is a test to demonstrate.

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

use Test::More tests => 1;

my $in   = q/xTest-1 [ ] 'copy'.png     /;
my $want = 'xTest-1copy.png';

my $have = filter ($in);

is $have, $want;

sub filter {
    my $str = shift or return '';
    return $str =~ tr/A-Za-z0-9.-//cdr;
}

[AnomalousMonk]

sub filter {
    my $str = shift or return '';
    return $str =~ tr/A-Za-z0-9.-//cdr;
}

The my $str = shift or return ''; statement will cause a file name of '0' to be converted to the empty string.

An alternative to avoid this problem is my ($str) = @_ or return '';

While such a file name seems unlikely to be encountered in the wild, it's best to be prepared. :)

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[hippo]

Good catch! When composing my test I initially had that line as

my $str = shift // '';

but the idea of doing the rest of the processing (however swift) against the empty string rankled so I opted for the short-circuit instead. Should have just left it well alone :-)

[AnomalousMonk]

First thought, best thought! :)