NAME

Set::Similarity::Jaccard - Jaccard coefficent for sets

SYNOPSIS

use Set::Similarity::Jaccard;

# object method
my $jaccard = Set::Similarity::Jaccard->new;
my $similarity = $jaccard->similarity('Photographer','Fotograf');

# class method
my $jaccard = 'Set::Similarity::Dice';
my $similarity = $jaccard->similarity('Photographer','Fotograf');

# from 2-grams
my $width = 2;
my $similarity = $jaccard->similarity('Photographer','Fotograf',$width);

# from arrayref of tokens
my $similarity = $jaccard->similarity(['a','b'],['b']);

# from hashref of features
my $bird = {
  wings    => true,
  eyes     => true,
  feathers => true,
  hairs    => false,
  legs     => true,
  arms     => false,
};
my $mammal = {
  wings    => false,
  eyes     => true,
  feathers => false,
  hairs    => true,
  legs     => true,
  arms     => true, 
};
my $similarity = $jaccard->similarity($bird,$mammal);

# from hashref sets
my $bird = {
  wings    => undef,
  eyes     => undef,
  feathers => undef,
  legs     => undef,
};
my $mammal = {
  eyes     => undef,
  hairs    => undef,
  legs     => undef,
  arms     => undef, 
};
my $similarity = $jaccard->from_sets($bird,$mammal); 

DESCRIPTION

Jaccard Index

The Jaccard coefficient measures similarity between sample sets, and is defined as the size of the intersection divided by the size of the union of the sample sets

( A intersect B ) / (A union B)

The Tanimoto coefficient is the ratio of the number of elements common to both sets to the total number of elements, i.e.

( A intersect B ) / ( A + B - ( A intersect B ) ) # the same as Jaccard

The range is 0 to 1 inclusive.

METHODS

Set::Similarity::Jaccard inherits all methods from Set::Similarity and implements the following new ones.

from_sets

my $similarity = $object->from_sets({'a' => undef},{'b' => undef});

SOURCE REPOSITORY

http://github.com/wollmers/Set-Similarity

AUTHOR

Helmut Wollmersdorfer, <helmut.wollmersdorfer@gmail.com>

COPYRIGHT AND LICENSE

Copyright (C) 2013 by Helmut Wollmersdorfer

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