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The array_keys function in php is used to return a new array containing all the key names in the array. This article introduces in detail how to use the PHP array_keys function. Coders who need it can refer to
array_keys returns some or all key names in the array
Instructions
array array_keys (array $array [, mixed $search_value [, bool $strict = false ]] )
array_keys() Returns the number or string key in the $array array name.
If the optional parameter search_value is specified, only the key name of the value will be returned. Otherwise all keys in the $array array will be returned.
Detailed explanation of parameters
| Parameters | Description |
|---|---|
| array | Required. An array containing the keys to be returned. |
| search_value | Optional. If this parameter is specified, only keys containing these values will be returned. |
| strict |
Optional. Used with the value parameter. Possible values:
|
Return value
Returns all keys in array.
Example
<?php
$array = array( 0 => 100 , "color" => "red" );
print_r ( array_keys ( $array ));
$array = array( "blue" , "red" , "green" , "blue" , "blue" );
print_r ( array_keys ( $array , "blue" ));
$array = array( "color" => array( "blue" , "red" , "green" ),
"size" => array( "small" , "medium" , "large" ));
print_r ( array_keys ( $array ));
?>
The above routine will output:
Array ( [0] => 0 [1] => color ) Array ( [0] => 0 [1] => 3 [2] => 4 ) Array ( [0] => color [1] => size )
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