Use isset with caution in PHP to determine whether an array has a key_PHP Tutorial

The article mainly talks about some examples about using isset with caution in PHP to determine whether there is a key in the array.

Connected to the code, I don’t know if it’s a problem with the php5.4 version, or if it’s just like this...

The code is as follows  代码如下 复制代码 $a['hello'] = ’123‘;  $a['xx'] = NULL;    var_dump(isset($a['hello'])); //bool(true)    var_dump(isset($a['xx'])); //bool(false)    # 应该使用这个来判断  var_dump(array_key_exists(‘xx’, $a)); //bool(true)	Copy code

$a['hello'] = ’123‘;
$a['xx'] = NULL;

var_dump(isset($a['hello'])); //bool(true)

var_dump(isset($a['xx'])); //bool(false)

# This should be used to judge
var_dump(array_key_exists(‘xx’, $a)); //bool(true)

http: //www.bkjia.com/PHPjc/628694.htmlThe article mainly talks about some examples about using isset with caution in PHP to determine whether there is a key in the array. Connected to the code, I don’t know if it’s a problem with the php5.4 version or it’s always like this. The code is as follows. Copy...