| Permute(3pm) | User Contributed Perl Documentation | Permute(3pm) |
String::Glob::Permute - Expand {foo,bar,baz}[2-4] style string globs
use String::Glob::Permute qw( string_glob_permute );
my $pattern = "host{foo,bar,baz}[2-4]";
for my $host (string_glob_permute( $pattern )) {
print "$host\n";
}
# hostfoo2
# hostbar2
# hostbaz2
# hostfoo3
# hostbar3
# hostbaz3
# hostfoo4
# hostbar4
# hostbaz4
The "string_glob_permute()" function provided by this module expands glob-like notations in text strings and returns all possible permutations.
For example, to run a script on hosts host1, host2, and host3, you might write
@hosts = string_glob_permute( "host[1-3]" );
and get a list of hosts back: ("host1", "host2", "host3").
Ranges with gaps are also supported, just separate the blocks by commas:
@hosts = string_glob_permute( "host[1-3,5,9]" );
will return ("host1", "host2", "host3", "host5", "host9").
And, finally, using curly brackets and comma-separated lists of strings, as in
@hosts = string_glob_permute( "host{dev,stag,prod}" );
you'll get permutations with each of the alternatives back: ("hostdev", "hoststag", "hostprod") back.
All of the above can be combined, so
my @hosts = string_glob_permute( "host{dev,stag}[3-4]" );
will result in the permutation ("hostdev3", "hoststag3", "hostdev4", "hoststag4").
The patterns allow numerical ranges only [1-3], no string ranges like [a-z]. Pattern must not contain blanks.
The function returns a list of string permutations on success and "undef" in case of an error. A warning is also issued if the pattern cannot be recognized.
An expression like
@hosts = string_glob_permute( "host[8-9,10]" );
# ("host8", "host9", "host10")
will expand to ("host8", "host9", "host10"), featuring no zero-padding to create equal-length entries. If you want ("host08", "host09", "host10"), instead, pad all integers in the range expression accordingly:
@hosts = string_glob_permute( "host[08-09,10]" );
# ("host08", "host09", "host10")
Note that there's a little-known feature within Perl itself that does something similar, for example
print "$_\n" for < foo{bar,baz} >;
will print
foobar
foobaz
if there is no file in the current directory that matches that pattern. String::Glob::Permute, on the other hand, expands irrespective of matching files, by simply always returning all possible permutations. It's also worth noting that Perl's internal Glob Permutation does not support String::Glob::Permute's [m,n] or [m-n] syntax.
Copyright (c) 2008 Yahoo! Inc. All rights reserved. The copyrights to the contents of this file are licensed under the Perl Artistic License (ver. 15 Aug 1997).
Algorithm, Code: Rick Reed, Ryan Hamilton, Greg Olszewski. Module: 2008, Mike Schilli <cpan@perlmeister.com>
| 2022-06-17 | perl v5.34.0 |