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Collator::getSortKey

collator_get_sort_key

(PHP 5 >= 5.3.2, PHP 7, PHP 8, PECL intl >= 1.0.3)

Collator::getSortKey -- collator_get_sort_key — Get sorting key for a string

Description

Object-oriented style

public Collator::getSortKey(string $string): string|false

Procedural style

collator_get_sort_key(Collator $object, string $string): string|false

Return collation key for a string. Collation keys can be compared directly instead of strings, though are implementation specific and may change between ICU library versions. Sort keys are generally only useful in databases or other circumstances where function calls are extremely expensive.

Parameters

object: Collator object.
string: The string to produce the key from.

Return Values

Returns the collation key for the string, or false on failure.

Warning

This function may return Boolean false, but may also return a non-Boolean value which evaluates to false. Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.

Examples

Example #1 collator_get_sort_key() example

<?php

$s1 = 'Hello';

$coll = collator_create('en_US');
$res  = collator_get_sort_key($coll, $s1);

echo bin2hex($res);
?>

The above example will output something similar to:

3832404046010901dc08

Example #2 Collator::getSortKey() example with usort()

<?php

$data = [
    [ 'name' => '🇳🇱 Derick Rethans', 'linked_account' => 'https://phpc.social/users/derickr' ],
    [ 'name' => 'Elephpant', 'linked_account' => 'https://phpc.social/phpc' ],
    [ 'name' => '🇫🇷 Marcus Bointon', 'linked_account' => 'https://phpc.social/users/Synchro' ],
];

/* Create the collator */
$col = new Collator('en');

/* Sort upper-case letters before lower-case letters */
$col->setAttribute(Collator::CASE_FIRST, Collator::UPPER_FIRST);

/* Use a user-defined function with sort, that strips out the emojis */
usort(
    $data,
    function($a, $b) use ($col) {
        /* Remove the character class 'S' (the Symbols), and remove whitespace
         * (with trim) */
        $aName = trim(preg_replace('/\p{S}+/u', '', $a['name']));
        $bName = trim(preg_replace('/\p{S}+/u', '', $b['name']));

                                /* Create the sort key */
        $aKey = $col->getSortKey($aName);
        $bKey = $col->getSortKey($bName);

                                /* Use the sort key to signal which element sorts first */
        return $aKey <=> $bKey;
    }
);

var_dump($data);
?>