NAME¶
Lucy::Analysis::RegexTokenizer - Split a string into tokens.
SYNOPSIS¶
my $whitespace_tokenizer
= Lucy::Analysis::RegexTokenizer->new( pattern => '\S+' );
# or...
my $word_char_tokenizer
= Lucy::Analysis::RegexTokenizer->new( pattern => '\w+' );
# or...
my $apostrophising_tokenizer = Lucy::Analysis::RegexTokenizer->new;
# Then... once you have a tokenizer, put it into a PolyAnalyzer:
my $polyanalyzer = Lucy::Analysis::PolyAnalyzer->new(
analyzers => [ $case_folder, $word_char_tokenizer, $stemmer ], );
DESCRIPTION¶
Generically, "tokenizing" is a process of breaking up a string into an
array of "tokens". For instance, the string "three blind
mice" might be tokenized into "three", "blind",
"mice".
Lucy::Analysis::RegexTokenizer decides where it should break up the text based
on a regular expression compiled from a supplied "pattern" matching
one token. If our source string is...
"Eats, Shoots and Leaves."
... then a "whitespace tokenizer" with a "pattern" of
"\\S+" produces...
Eats,
Shoots
and
Leaves.
... while a "word character tokenizer" with a "pattern" of
"\\w+" produces...
Eats
Shoots
and
Leaves
... the difference being that the word character tokenizer skips over
punctuation as well as whitespace when determining token boundaries.
CONSTRUCTORS¶
new( [labeled params] )¶
my $word_char_tokenizer = Lucy::Analysis::RegexTokenizer->new(
pattern => '\w+', # required
);
- •
- pattern - A string specifying a Perl-syntax regular expression
which should match one token. The default value is
"\w+(?:[\x{2019}']\w+)*", which matches "it's" as well
as "it" and "O'Henry's" as well as
"Henry".
INHERITANCE¶
Lucy::Analysis::RegexTokenizer isa Lucy::Analysis::Analyzer isa
Lucy::Object::Obj.