property_exists

Function name: property_exists()

Function Description: property_exists() function checks whether an object or class has the specified attribute.

parameter:

• $class: Required. The class name or object to be checked.
• $property: Required. The attribute name to check.

Return value:

• Returns true if the property exists and is accessible.
• If the property does not exist or is inaccessible, false is returned.

Applicable version: PHP 4, PHP 5, PHP 7

Usage example:

1. Check whether the class has the specified attribute:

 class MyClass { public $name = "John"; private $age = 25; } $object = new MyClass(); if (property_exists($object, 'name')) { echo "The 'name' property exists."; } else { echo "The 'name' property does not exist."; } // 输出：The 'name' property exists.

2. Check whether the object has the specified attribute:

 class MyClass { public $name = "John"; private $age = 25; } $object = new MyClass(); if (property_exists($object, 'age')) { echo "The 'age' property exists."; } else { echo "The 'age' property does not exist."; } // 输出：The 'age' property does not exist.

3. Check whether the class name has the specified static attribute:

 class MyClass { public static $name = "John"; private static $age = 25; } if (property_exists('MyClass', 'name')) { echo "The 'name' static property exists."; } else { echo "The 'name' static property does not exist."; } // 输出：The 'name' static property exists.

4. Check whether the class name has the specified static private attribute:

 class MyClass { public static $name = "John"; private static $age = 25; } if (property_exists('MyClass', 'age')) { echo "The 'age' static property exists."; } else { echo "The 'age' static property does not exist."; } // 输出：The 'age' static property does not exist.