How Can I Efficiently Search for a Value and Retrieve Its Key in a PHP Multidimensional Array?

PHP Multidimensional Array Search by Value

Problem:

Given a multidimensional array, how can you efficiently search for a specific value (e.g., a user ID) and retrieve its corresponding array key?

Solution:

Below are two approaches to search for a value in a multidimensional array and obtain its key:

Method 1: Using Loops

function search_by_uid($id, $array) {
    foreach ($array as $key => $val) {
        if ($val['uid'] === $id) {
            return $key;
        }
    }
    return null;
}

Method 2: Using array_search with array_column (PHP 5.5.0 and above)

$key = array_search('100', array_column($userdb, 'uid'));

Calling the Functions:

To use these functions:

• Method 1:

  • $key = search_by_uid('100', $userdb);

• Method 2:

  • $key = array_search('100', array_column($userdb, 'uid'));

The $key variable will contain the array key of the found value (or null if not found).

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