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HomeBackend DevelopmentPHP Tutorialphp数组函数序列之array_values() 获取数组元素值的函数与方法_php技巧

array_values() 定义和用法
array_keys() 函数返回包含数组中所有键名的一个新数组。

如果提供了第二个参数,则只返回键值为该值的键名。

如果 strict 参数指定为 true,则 PHP 会使用全等比较 (===) 来严格检查键值的数据类型。

语法
array_keys(array,value)
参数 描述
array 必需。规定输入的数组。
value 可选。指定值的索引(键)。
strict 可选。与 value 参数一起使用。可能的值:

true - 根据类型返回带有指定值的键名。
false - 默认值。不依赖类型。


例子 1

复制代码 代码如下:

$a=array("a"=>"Horse","b"=>"Cat","c"=>"Dog");
print_r(array_keys($a));
?>

输出:

Array ( [0] => a [1] => b [2] => c )
例子 2
使用 value 参数:
复制代码 代码如下:

$a=array("a"=>"Horse","b"=>"Cat","c"=>"Dog");
print_r(array_keys($a,"Dog"));
?>

输出:

Array ( [0] => c)
例子 3
使用 strict 参数 (false):
复制代码 代码如下:

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

输出:

Array ( [0] => 0 [1] => 3 )
例子 4
使用 strict 参数 (true):
复制代码 代码如下:

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

输出:

Array ( [0] => 3)
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