A simple TF–IDF example in PHP

Below is a minimal TF–IDF implementation in pure PHP. We take three short documents (about a cat and a dog), build a vocabulary, compute TF and IDF, and then produce TF–IDF weights for each term in each document.

Example of use


                
<?php

// Source documents for TF-IDF calculation.
$documents = [
    'The cat eats fish',
    'The cat loves fish',
    'The dog eats canned meat',
];

include 'code.php';

echo 'Vocabulary: ' . implode(', ', $vocab) . PHP_EOL . PHP_EOL;

foreach ($tfidfVectors as $i => $vector) {
    echo 'Document ' . ($i + 1) . ':' . PHP_EOL;

    foreach ($vector as $word => $value) {
        echo "  $word => " . round($value, 3) . PHP_EOL;
    }

    if ($i < 2) {
        echo PHP_EOL;
    }
}

Documents:


            The cat eats fish
The cat loves fish
The dog eats canned meat

Result: Memory: 0.01 Mb Time running: 0.002 sec.


                Vocabulary: The, cat, eats, fish, loves, dog, canned, meat

Document 1:
  The => 0
  cat => 0.101
  eats => 0.101
  fish => 0.101

Document 2:
  The => 0
  cat => 0.101
  loves => 0.275
  fish => 0.101

Document 3:
  The => 0
  dog => 0.22
  eats => 0.081
  canned => 0.22
  meat => 0.22