apply a regular expression to glob'd filenames

flieckster has asked for the wisdom of the Perl Monks concerning the following question:

hello all, i'd like to apply a regular expression after i glob some filenames from a directory. the files in question are .tif files, and i'd like to remove the file extensions from them to use later. I tried grep with a regex and it isn't returning what i'd like.

chdir( $wetrasnfer) or mail ($to = $internaldl, $from = $internaldl, $
+subject= "wetransfer $! $0", $body ="ERROR $wetrasnfer $! $0" );
(@wetransfer) = glob '*.tif';
@wetrasnfer_fix = grep /([0-9])*_([0-9]*)/, @wetransfer;
print join("\n", @wetrasnfer_fix), "\n";
[download]

the code above results in returning the full filename.

00204597_957.tif
00271558_148.tif
00271558_585.tif
[download]

ideally i'd want above returned with the .tif missing.

Comment on apply a regular expression to glob'd filenames Select or Download Code

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Re: apply a regular expression to glob'd filenames by choroba (Cardinal) on Oct 01, 2019 at 20:26 UTC
grep is for filtering, map is for transforming. `my @wetrasnfer_fix = map /([0-9]_[0-9])/, @wetransfer;` [download] With 5.14+, you can also use the "return" substitution modifier: `my @wetrasnfer_fix = map s/\.tif$//r, @wetransfer;` [download] Or, you can use split: `my @wetrasnfer_fix = map +(split /\./)[0], @wetransfer;` [download] Note from stevieb: You should also handle the case when not only the chdir fails, but the `mail` fails, too. `map{substr$_->[0],$_->[1]\|\|0,1}[\\|\|{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^ARGV,3]`	[reply] [d/l] [select]
Re^2: apply a regular expression to glob'd filenames by flieckster (Scribe) on Oct 02, 2019 at 14:31 UTC
ahh, thank you. the map worked perfectly!	[reply]
Re: apply a regular expression to glob'd filenames by Fletch (Bishop) on Oct 01, 2019 at 20:28 UTC
grep returns items from a list for which the predicate returns true. You want to map the list of matching filenames to remove the extension. `@wetransfer_fix = map { (my $t = $_) =~ s/\.tif//; $t } grep # ...as b +efore...` [download] Also someone else mentioned in the chatterbox that you might want to change how you're doing error handling on your initial chdir and die so you don't continue trying to run in the wrong directory. `unless( chdir( $wetrasnfer ) ) { my $chdir_error = $!; ## In case mail() clobbers old value mail( ... blah ... ); ## send email notification die qq{Couldn't send error mail: $chdir_error\n}; }` [download] The cake is a lie. The cake is a lie. The cake is a lie.	[reply] [d/l] [select]
Re: apply a regular expression to glob'd filenames by 1nickt (Canon) on Oct 01, 2019 at 20:58 UTC
Hi, this is not a job for a regexp. Use the core module File::Basename to handle stripping extensions, or even better use Path::Tiny or Path::Iterator::Rule to find the files and get your desired output. Here's one way: `$ ls /tmp/11106920/` [download] `123456.tif 123_456.tif 666_666.jpeg 678_910.tif` [download] `$ perl -Mstrict -MPath::Tiny -wE 'path("/tmp/11106920")->visit( sub { +say $_->basename(".tif") if /[0-9]+_[0-9]+\.tif/ } );'` [download] `678_910 123_456` [download] Hope this helps! The way forward always starts with a minimal test.	[reply] [d/l] [select]
Re: apply a regular expression to glob'd filenames by hippo (Archbishop) on Oct 01, 2019 at 21:06 UTC
TIMTOWTDI. Here's an approach using a `for` loop. `use strict; use warnings; use Test::More tests => 1; my @have = qw/00204597_957.tif 00271558_148.tif 00271558_585.tif/; my @want = qw/00204597_957 00271558_148 00271558_585/; s/\..*// for @have; is_deeply \@have, \@want;` [download]	[reply] [d/l] [select]