Sort Array by amount of matches and put best fit first php

Question

I create a tag based search and want to sort the search result according to the relevance. The best fit and the number of tags are relevant. Imagine this is the search query:

$search = ['A', 'B'];

and this the result:

$result = [
  [
    'id' => 3011,
    'tags' => ['A', 'B', 'C']
  ],
  [
    'id' => 10798,
    'tags' => ['A','C','D','E']
  ],
  [
    'id' => 92,
    'tags' => ['A']
  ],
  [
    'id' => 4237,
    'tags' => ['A', 'B']
  ]
];

I want to reorganize the whole thing as follows:

$sortResult = [
  [
    'id' => 4237,
    'tags' => ['A', 'B'] // At first place because has 2 values and the search 2, difference 0 and matched good to search
  ],
  [
    'id' => 3011,
    'tags' => ['A', 'B', 'C'] // At second place because has 3 values and the search 2, difference 1 and matched good to search
  ],
  [
    'id' => 92,
    'tags' => ['A'] // At third place because has 1 value and the search 2, difference 1
  ],
  [
    'id' => 10798,
    'tags' => ['A','C','D','E'] // Down here because has 4 values and the search 2, difference 2
  ]
];

Answer 1

Not sure if this works in all cases but it gives the desired result for your current data:

<?php
$search = ['A', 'B'];

$result = [
[
    'id' => 3011,
    'tags' => ['A', 'B', 'C'],
],
[
    'id' => 10798,
    'tags' => ['A', 'C', 'D', 'E'],
],
[
    'id' => 92,
    'tags' => ['A'],
],
[
    'id' => 4237,
    'tags' => ['A', 'B'],
],
];

usort($result, function ($a, $b) use ($search) {
    $simA = count(array_intersect($a['tags'], $search));
    $simB = count(array_intersect($b['tags'], $search));
    $diffA = count(array_diff($a['tags'], $search));
    $diffB = count(array_diff($b['tags'], $search));
    $absA = abs(count($a['tags']) - count($search));
    $absB = abs(count($b['tags']) - count($search));

    $score = 0;

    $score += $simB - $simA;
    $score += $diffA - $diffB;
    $score += $absA - $absB;

    return $score;
});

echo '<pre>';
print_r($result);
echo '</pre>';

http://phpio.net/s/7yhb