PHP function array_keys() returns a new array containing all the key names in the array-PHP Tutorial-php.cn

Example

Returns a new array containing all the key names in the array:

<?php
$a=array("Volvo"=>"XC90","BMW"=>"X5","Toyota"=>"Highlander");
print_r(array_keys($a));
?>

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Definition and usage

array_keys() function returns the value containing A new array of all keys in the array.

Syntax

array_keys(array,value,strict)

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Parameters	Description
array	Required. Specifies an array.
value	Optional. You can specify a key value, and then only the key name corresponding to that key value will be returned.
strict	Optional. Used with the value parameter. Possible values: true - Returns the key name with the specified key value. Depending on the type, the number 5 is different from the string "5". false - Default value. Independent of type, the number 5 is the same as the string "5".

Technical details

The strict parameter is

更多实例

实例 1

使用 value 参数：

<?php
$a=array("Volvo"=>"XC90","BMW"=>"X5","Toyota"=>"Highlander");
print_r(array_keys($a,"Highlander"));
?>

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实例 2

使用 strict 参数 (false)：

<?php
$a=array(10,20,30,"10");
print_r(array_keys($a,"10",false));
?>

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实例 3

使用 strict 参数 (true)：

<?php
$a=array(10,20,30,"10");
print_r(array_keys($a,"10",true));
?>

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Return value:	Returns a new array containing all keys in the array.
PHP Version:	4+
##Update Log :	new in PHP 5.0.