Definition
The array_keys() function returns all the keys or a subset of the keys of an array.
Syntax
array_keys(array, value, strict)
Parameters
| Parameter | Description |
|---|---|
array |
Required. Specifies an array. |
value |
Optional. You can specify a value, then only the keys with this value are returned. |
strict |
Optional. Possible values: true - Returns the keys with the specified value, depending on type: the number 5 is not the same as the string "5"; false - Default value. Not depending on type, the number 5 is the same as the string "5". |
Example
<?php
$ages = array("Mark" => 22, "Jeff" => 32, "Mike" => 28);
print_r(array_keys($ages));
echo "<br>";
// Using the `values` parameter
print_r(array_keys($ages, 32));
echo "<br>";
// Using the `strict` parameter
print_r(array_keys($ages, "32", false));
echo "<br>";