1Lucy::Analysis::SnowbalUlsSetropCFoinlttreirb(u3t)ed PerLlucDyo:c:uAmneanltyastiiso:n:SnowballStopFilter(3)
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NAME

6       Lucy::Analysis::SnowballStopFilter - Suppress a “stoplist” of common
7       words.
8

SYNOPSIS

10           my $stopfilter = Lucy::Analysis::SnowballStopFilter->new(
11               language => 'fr',
12           );
13           my $polyanalyzer = Lucy::Analysis::PolyAnalyzer->new(
14               analyzers => [ $tokenizer, $normalizer, $stopfilter, $stemmer ],
15           );
16

DESCRIPTION

18       A “stoplist” is collection of “stopwords”: words which are common
19       enough to be of little value when determining search results.  For
20       example, so many documents in English contain “the”, “if”, and “maybe”
21       that it may improve both performance and relevance to block them.
22
23       Before filtering stopwords:
24
25           ("i", "am", "the", "walrus")
26
27       After filtering stopwords:
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29           ("walrus")
30
31       SnowballStopFilter provides default stoplists for several languages,
32       courtesy of the Snowball project <http://snowball.tartarus.org>, or you
33       may supply your own.
34
35           |-----------------------|
36           | ISO CODE | LANGUAGE   |
37           |-----------------------|
38           | da       | Danish     |
39           | de       | German     |
40           | en       | English    |
41           | es       | Spanish    |
42           | fi       | Finnish    |
43           | fr       | French     |
44           | hu       | Hungarian  |
45           | it       | Italian    |
46           | nl       | Dutch      |
47           | no       | Norwegian  |
48           | pt       | Portuguese |
49           | sv       | Swedish    |
50           | ru       | Russian    |
51           |-----------------------|
52

CONSTRUCTORS

54   new
55           my $stopfilter = Lucy::Analysis::SnowballStopFilter->new(
56               language => 'de',
57           );
58
59           # or...
60           my $stopfilter = Lucy::Analysis::SnowballStopFilter->new(
61               stoplist => \%stoplist,
62           );
63
64       Create a new SnowballStopFilter.
65
66       •   stoplist - A hash with stopwords as the keys.
67
68       •   language - The ISO code for a supported language.
69

METHODS

71   transform
72           my $inversion = $snowball_stop_filter->transform($inversion);
73
74       Take a single Inversion as input and returns an Inversion, either the
75       same one (presumably transformed in some way), or a new one.
76
77       •   inversion - An inversion.
78

INHERITANCE

80       Lucy::Analysis::SnowballStopFilter isa Lucy::Analysis::Analyzer isa
81       Clownfish::Obj.
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85perl v5.36.0                      2023-01-L2u0cy::Analysis::SnowballStopFilter(3)
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