http://qs321.pair.com?node_id=311589


in reply to Finding un-paired files in a directory

Here's my implementation -
use strict;
use Data::Dumper;

chomp(my @files = <DATA>);

# find unique basenames
my @basenames = keys %{{ map { (split/\./)[0] => 1 } @files }};

# find unpaired files
foreach my $basename (@basenames) {
    my @matches = grep (/$basename/, @files);
    print "$matches[0]\n" if $#matches == 0;
}

__DATA__
00000001.did
00000001.mrg
00000002.did
00000002.mrg
00000003.did
00000004.mrg

[download]
And the output -
00000004.mrg
00000003.did

[download]

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•Re: Re: Finding un-paired files in a directory
by merlyn (Sage) on Dec 02, 2003 at 12:16 UTC 
    use strict;
use Data::Dumper;

chomp(my @files = <DATA>);

# find unique basenames
my @basenames = keys %{{ map { (split/\./)[0] => 1 } @files }};

# find unpaired files
foreach my $basename (@basenames) {
    my @matches = grep (/$basename/, @files);
    print "$matches[0]\n" if $#matches == 0;
}

    [download]
    No, this solution breaks if any filenames have regex-significant metachars, or are partially within a larger filename.

    In my opinion, the original solution is actually the most direct, as this is a classic set difference problem.

    -- Randal L. Schwartz, Perl hacker
    Be sure to read my standard disclaimer if this is a reply.

[reply]
[d/l]

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