Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/robrwo/set-light

(memory efficient) unordered set of strings
https://github.com/robrwo/set-light

Last synced: 11 days ago
JSON representation

(memory efficient) unordered set of strings

Awesome Lists containing this project

README 

        
# NAME



Set::Light - (memory efficient) unordered set of strings



# VERSION



version 0.95



# SYNOPSIS



```perl

use Set::Light;



my $set = Set::Light->new( qw/foo bar baz/ );



if (!$set->is_empty())

{

  print "Set has ", $set->size(), " elements.\n";

  for (qw/umpf foo bar baz bam/)

  {

      print "Set does ";

      print " not " unless $set->has($_);

      print "contain '$_'.\n";

  }

}

```



# DESCRIPTION



Set::Light implements an unordered set of strings. Set::Light

currently uses a hash underneath, and each key of the hash points to

the same scalar, thus saving memory per item.



## Why not use a hash?



Usually you would use a hash to keep track of a list of items like:



```perl

my %SEEN;



...



if (!$SEEN->{$item}++)

{

  # haven't seen item before

}

```



While this is very fast (both on inserting items, as well as looking them up),

it uses quite a lot of memory, since each key in `%SEEN` needs one scalar.



## Why not use Set::Object or Set::Scalar?



These use even more memory and/or are slower than an ordinary hash.



# METHODS



## new



```perl

my $set = Set::Light->new( \%opts, @members );

```



Creates a new Set::Light object. An optionally passed hash reference can

contain options.



Any members passed to the constructor will be inserted.



Currently no options are supported.



## insert



```

$set->insert( $string );

$set->insert( @strings );

```



Inserts one or more strings into the set. Returns the number of insertions

it really did. Elements that are already contained in the set do not

get inserted twice. So:



```perl

use Set::Light;



my $set = Set::Light->new();

print $set->insert('foo');              # 1

print $set->insert('foo');              # 0

print $set->insert('bar','baz','foo');  # 2     (foo already inserted)

```



## is\_empty



```

if (!$set->is_empty()) { ... }

```



Returns true if the set is empty (has zero elements).



## is\_null



This is an alias to ["is\_empty"](#is_empty).



## size



```perl

my $elems = $set->size();

```



Returns the number of elements in the set.



## has



```

if ($set->has($member)) { ... }

```



Returns true if the set contains the string `$member`.



## contains



This is an alias for ["has"](#has).



## exists



This is an alias for ["has"](#has).



## delete



```

$set->delete( $string );

$set->delete( @strings );

```



Deletes one or more strings from the set. Returns the number of

deletions it really did. Elements that are not contained in the set

cannot be deleted.  So:



```perl

use Set::Light;



my $set = Set::Light->new();

print $set->insert('foo','bar');      # 2

print $set->delete('foo','foo');      # 1     (only once deleted)

pprint $set->delete('bar','foo');     # 1     (only once deleted)

```



## remove



This is an alias for ["delete"](#delete).



## members



```perl

my @members = $set->members;

```



This returns an array of set members in an unsorted array.



This was added in v0.91.



# SEE ALSO



[Set::Object](https://metacpan.org/pod/Set::Object), [Set::Scalar](https://metacpan.org/pod/Set::Scalar).



# SOURCE



The development version is on github at [https://github.com/robrwo/Set-Light](https://github.com/robrwo/Set-Light)

and may be cloned from [git://github.com/robrwo/Set-Light.git](git://github.com/robrwo/Set-Light.git)



# BUGS



Please report any bugs or feature requests on the bugtracker website

[https://github.com/robrwo/Set-Light/issues](https://github.com/robrwo/Set-Light/issues)



When submitting a bug or request, please include a test-file or a

patch to an existing test-file that illustrates the bug or desired

feature.



# AUTHOR



Tels 



# CONTRIBUTOR



Robert Rothenberg 



# COPYRIGHT AND LICENSE



This software is copyright (c) 2004-2008, 2019-2021 by Tels.



This is free software; you can redistribute it and/or modify it under

the same terms as the Perl 5 programming language system itself.