(PHP 4 >= 4.0.7, PHP 5, PHP 7, PHP 8)
array_key_exists — Checks if the given key or index exists in the array
array_key_exists() returns true
if the
given key
is set in the array.
key
can be any value possible
for an array index.
key
Value to check.
array
An array with keys to check.
Повертає true
у разі успіху або false
в разі помилки.
Зауваження:
array_key_exists() will search for the keys in the first dimension only. Nested keys in multidimensional arrays will not be found.
Версія | Опис |
---|---|
8.0.0 |
The key parameter now accepts
bool , float , int ,
null , resource , and
string as arguments.
|
Приклад #1 array_key_exists() example
<?php
$search_array = array('first' => 1, 'second' => 4);
if (array_key_exists('first', $search_array)) {
echo "The 'first' element is in the array";
}
?>
Приклад #2 array_key_exists() vs isset()
isset() does not return true
for array keys
that correspond to a null
value, while
array_key_exists() does.
<?php
$search_array = array('first' => null, 'second' => 4);
// returns false
isset($search_array['first']);
// returns true
array_key_exists('first', $search_array);
?>
Зауваження:
For backward compatibility reasons, array_key_exists() will also return
true
ifkey
is a property defined within an object given asarray
. This behaviour is deprecated as of PHP 7.4.0, and removed as of PHP 8.0.0.To check whether a property exists in an object, property_exists() should be used.