Login or Register to Ask a Question and Join Our Community

Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

hash::case(3pm) [debian man page]

Hash::Case(3pm) 					User Contributed Perl Documentation					   Hash::Case(3pm)

NAME

       Hash::Case - base class for hashes with key-casing requirements

INHERITANCE

	Hash::Case
	  is a Tie::StdHash

	Hash::Case is extended by
	  Hash::Case::Lower
	  Hash::Case::Preserve
	  Hash::Case::Upper

SYNOPSIS

	use Hash::Case::Lower;
	tie my(%lchash), 'Hash::Case::Lower';
	$lchash{StraNGeKeY} = 3;
	print keys %lchash;  # strangekey

DESCRIPTION

       Hash::Case is the base class for various classes which tie special treatment for the casing of keys.  Be aware of the differences in
       implementation: "Lower" and "Upper" are tied native hashes: these hashes have no need for hidden fields or other assisting data structured.
       A case "Preserve" hash will actually create three hashes.

       The following strategies are implemented:

       o   Hash::Case::Lower (native hash)

	   Keys are always considered lower case. The internals of this module translate any incoming key to lower case before it is used.

       o   Hash::Case::Upper (native hash)

	   Like the ::Lower, but then all keys are always translated into upper case.  This module can be of use for some databases, which do
	   translate everything to capitals as well.  To avoid confusion, you may want to have you own internal Perl hash do this as well.

       o   Hash::Case::Preserve

	   The actual casing is ignored, but not forgotten.

METHODS

   Constructors
       $obj->addHashData(HASH)
	   Add the data of a hash (passed as reference) to the created tied hash.  The existing values in the hash remain, the keys are adapted to
	   the needs of the the casing.

       $obj->addPairs(PAIRS)
	   Specify an even length list of alternating key and value to be stored in the hash.

       $obj->setHash(HASH)
	   The functionality differs for native and wrapper hashes.  For native hashes, this is the same as first clearing the hash, and then a
	   call to addHashData().  Wrapper hashes will use the hash you specify here to store the data, and re-create the mapping hash.

       tie(HASH, TIE, [VALUES,] OPTIONS)
	   Tie the HASH with the TIE package which extends Hash::Case.	The OPTIONS differ per implementation: read the manual page for the
	   package you actually use.  The VALUES is a reference to an array containing key-value pairs, or a reference to a hash: they fill the
	   initial hash.

	   example:

	    my %x;
	    tie %x, 'Hash::Case::Lower';
	    $x{Upper} = 3;
	    print keys %x;	 # 'upper'

	    my @y = (ABC => 3, DeF => 4);
	    tie %x, 'Hash::Case::Lower', @y;
	    print keys %x;	 # 'abc' 'def'

	    my %z = (ABC => 3, DeF => 4);
	    tie %x, 'Hash::Case::Lower', \%z;

SEE ALSO

       This module is part of Hash-Case distribution version 1.02, built on March 09, 2012. Website: http://perl.overmeer.net/hash-case/

LICENSE

       Copyrights 2002-2003,2007-2012 by Mark Overmeer. For other contributors see ChangeLog.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.  See
       http://www.perl.com/perl/misc/Artistic.html

perl v5.14.2							    2012-03-09							   Hash::Case(3pm)

Check Out this Related Man Page

Tie::Hash::Regex(3pm)					User Contributed Perl Documentation				     Tie::Hash::Regex(3pm)

NAME

       Tie::Hash::Regex - Match hash keys using Regular Expressions

SYNOPSIS

	 use Tie::Hash::Regex;
	 my %h;

	 tie %h, 'Tie::Hash::Regex';

	 $h{key}   = 'value';
	 $h{key2}  = 'another value';
	 $h{stuff} = 'something else';

	 print $h{key};  # prints 'value'
	 print $h{2};	 # prints 'another value'
	 print $h{'^s'}; # prints 'something else'

	 print tied(%h)->FETCH(k); # prints 'value' and 'another value'

	 delete $h{k};	 # deletes $h{key} and $h{key2};

       or (new! improved!)

	 my $h : Regex;

DESCRIPTION

       Someone asked on Perlmonks if a hash could do fuzzy matches on keys - this is the result.

       If there's no exact match on the key that you pass to the hash, then the key is treated as a regex and the first matching key is returned.
       You can force it to leap straight into the regex checking by passing a qr'ed regex into the hash like this:

	 my $val = $h{qr/key/};

       "exists" and "delete" also do regex matching. In the case of "delete" all vlaues matching your regex key will be deleted from the hash.

       One slightly strange thing. Obviously if you give a hash a regex key, then it's possible that more than one key will match (consider
       c<$h{qw/./}>).  It might be nice to be able to do stuff like:

	 my @vals = $h{$pat};

       to get all matching values back. Unfortuately, Perl knows that a given hash key can only ever return one value and so forces scalar context
       on the "FETCH" call when using the tied interface. You can get round this using the slightly less readable:

	 my @vals = tied(%h)->FETCH($pat);

   ATTRIBUTE INTERFACE
       From version 0.06, you can use attributes to define your hash as being tied to Tie::Hash::Regex. You'll need to install the module
       Attribute::Handlers.

METHODS

   FETCH
       Get a value from the hash. If there isn't an exact match try a regex match.

   EXISTS
       See if a key exists in the hash. If there isn't an exact match try a regex match.

   DELETE
       Delete a key from the hash. If there isn't an exact match try a regex match.

AUTHOR

       Dave Cross <dave@mag-sol.com>

       Thanks to the Perlmonks <http://www.perlmonks.org> for the original idea and to Jeff "japhy" Pinyan for some useful code suggestions.

COPYRIGHT

       Copyright (C) 2001-8, Magnum Solutions Ltd.  All Rights Reserved.

LICENSE

       This script is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

       perl(1).

       perltie(1).

       Tie::RegexpHash(1)

perl v5.10.0							    2008-06-30						     Tie::Hash::Regex(3pm)
Man Page