


PHP object-oriented-detailed code examples of __tostring() and __invoke()
tostring()Magic method
When an object is used as a string, it will This method is automatically called, and in this method, a certain string can be returned to indicate the result of converting the object into a string. This magic method is relatively common.
Note: If this method is not defined, the object cannot be used as a string!
Example of undefined tostring() method in class:
<?php ini_set('display_errors', 1); class A{ public $name; public $age; public $sex; function construct($name, $age, $sex){ $this->name = $name; $this->age = $age; $this->sex = $sex; } } $obj1 = new A('张三', 15, '男'); echo $obj1; //echo 后面为字符串,而对象不是字符串,会报错 $v1 = "abc" . $obj1; //.为字符串连接符,会报错 $v2 = "abx" + $obj1; //+为加法运算符,会报错?>
The three error contents are
Catchable fatal error: Object of class A could not be converted to string Catchable fatal error: Object of class A could not be converted to string Notice: Object of class A could not be converted to int
The tostring() method is defined in the class
<?php ini_set('display_errors', 1); class A{ public $name; public $age; public $sex; function construct($name, $age, $sex){ $this->name = $name; $this->age = $age; $this->sex = $sex; } function tostring(){ $str = "姓名:" . $this->name; $str .= "年龄:" . $this->age; $str .= ",性别:" . $this->sex; return $str; //这里可以返回“任何字符串内容” } } $obj1 = new A('张三', 15, '男'); echo $obj1; //调用tostring(),不会报错?>
Running result
姓名:张三年龄:15,性别:男
invoke() magic method
This method will be called automatically when the object is used as a function. This is generally not recommended.
class A{ function invoke(){ echo "<br />我是一个对象呀,你别把我当作一个函数来调用啊!"; } }$obj = new A();$obj(); //此时就会调用类中的方法:invoke()
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