Re: Extract string from rear of string

[thunders]

Update: Juerd is correct in his post below. I made a mistake in my post regarding the split operator. I have corrected this.

Here is an example of File::Basename, applied to the current directory. This is not perfect, but should get you started.

#/usr/bin/perl -w

use File::Basename;
use strict;

my @files = <*>;

foreach my $file (@files) {
    my ($name,$dir,$type) = fileparse($file,'\..*');
    print sprintf("file= %30s", $name), sprintf("  ext= %10s", $type),
+"\n";

}

you can refine this by crafting a better regex as the second argument to fileparse. This module is overkill unless you are dealing with full filepaths. for a single directory you could just use

my($filename,$ext) = split(/\./,$file);

or something similar.

[Juerd]

print sprintf("file= %30s", $name), sprintf(" ext= %10s", $type),"\n";

Personally, I'd use:


printf "file = %30s  ext= %10s\n", $name, $type;

my($filename,$ext) = split('\..*',$file);

While this is valid syntax, using a string as split's first argument might be confusing to beginners. Every string that is not a single space (\x20) is interpreted as a regex. Using slashes or another m// makes your intention clear.


my ($filename, $ext) = split /\..*/, $file;

Splitting on /\..*/ would return ('foo', undef) for 'foo.bar'.
Splitting on /\./ would probably fix this, but you don't want ('foo', 'bar', 'baz') or (using a limit) ('foo', 'bar.baz').
So using a regex without split would probably be best:

my ($filename, $ext) = $file =~ /^(.+)(?:\.(.*))?$/s

(The first .+ will grab as much as it can, because it is greedy. The /s was added just in case someone has a linefeed in his filename, the anchors are there just to clarify the code, they don't serve a real. I used .+ for dotfiles (filenames beginning with a dot are hidden files in *nix). The extention part is optional ( (?:)? ) because not all files have an extention.)


2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$