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Re: improving speed in ngrams algorithm

by johngg (Canon)
on Jun 12, 2019 at 10:21 UTC ( #11101277=note: print w/replies, xml ) Need Help??


in reply to improving speed in ngrams algorithm

A solution using split, array slices and shift. No idea if it is fast or slow as I haven't run any benchmarks.

use 5.026; use warnings; my $text = q{this is the text to play with}; for ( 1 .. 8 ) { say qq{$_-word ngrams of '$text'}; say for nGramWords( $_, $text ); say q{-} x 20; } sub nGramWords { my( $nWords, $string ) = @_; my @words = split m{\s+}, $string; my $start = 0; my @nGrams; while ( scalar @words >= $nWords ) { push @nGrams, join q{ }, qq{START INDEX: @{ [ $start ++ ] } : }, @words[ 0 .. $nWords - 1 ]; shift @words; } return @nGrams; }

The output.

1-word ngrams of 'this is the text to play with' START INDEX: 0 : this START INDEX: 1 : is START INDEX: 2 : the START INDEX: 3 : text START INDEX: 4 : to START INDEX: 5 : play START INDEX: 6 : with -------------------- 2-word ngrams of 'this is the text to play with' START INDEX: 0 : this is START INDEX: 1 : is the START INDEX: 2 : the text START INDEX: 3 : text to START INDEX: 4 : to play START INDEX: 5 : play with -------------------- 3-word ngrams of 'this is the text to play with' START INDEX: 0 : this is the START INDEX: 1 : is the text START INDEX: 2 : the text to START INDEX: 3 : text to play START INDEX: 4 : to play with -------------------- 4-word ngrams of 'this is the text to play with' START INDEX: 0 : this is the text START INDEX: 1 : is the text to START INDEX: 2 : the text to play START INDEX: 3 : text to play with -------------------- 5-word ngrams of 'this is the text to play with' START INDEX: 0 : this is the text to START INDEX: 1 : is the text to play START INDEX: 2 : the text to play with -------------------- 6-word ngrams of 'this is the text to play with' START INDEX: 0 : this is the text to play START INDEX: 1 : is the text to play with -------------------- 7-word ngrams of 'this is the text to play with' START INDEX: 0 : this is the text to play with -------------------- 8-word ngrams of 'this is the text to play with' --------------------

I hope this is of interest.

Cheers,

JohnGG

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