Simple comparison: multiple ways to call class methods in PHP classes

In PHP, class is a very important concept. Classes provide a way to encapsulate code, making it more maintainable and easier to understand. Members of a class include properties and methods. Class attributes can be any type of data, including scalar types, array types, and object types. A class method is a block of code that performs some task. In PHP, we can call class methods in many ways. Let's take a closer look at the differences between these methods.

1. Calling object methods

In PHP, we can call methods defined in a class by instantiating an object. The basic syntax for instantiating an object is: $object = new MyClass(). Among them, MyClass is a class name, and $object is an instantiation object of this class. If there is a method defined in this class named foo(), then we can call it in the following way:

$object->foo();

where'- >' is the object operator in PHP, which is used to access object properties and methods. This method is the most common way to call class methods.

2. Calling static methods

Another way to call class methods is to call static methods. Unlike calling object methods, static methods are called without instantiating the object. If there is a static method named bar() in the class, then we can call it in the following way:

MyClass::bar();

where '::' is PHP The static operator in , which is used to access static properties and methods. The advantage of calling static methods is that there is no need to create an instantiated object, thus avoiding some unnecessary overhead. In addition, static methods can also be used to perform some operations that have nothing to do with the state of the object.

3. Call the parent class method

In the inheritance relationship, the subclass can inherit the properties and methods of the parent class. If a method with the same name is also defined in the subclass, then we can call the method of the parent class through parent::. Assume that the parent class is ParentClass and the subclass is ChildClass. There is a method named baz() in the parent class and there is a method with the same name in the subclass. Then we can call the baz() method of the parent class in the following way:

parent::baz();

It should be noted that if the baz() method in the parent class is defined as private or protected, it is inaccessible in the subclass.

4. Call its own methods

Sometimes, methods in a class need to call other methods of the class itself. In PHP, we can access members of a class through $this. $this is a reference that represents the currently instantiated object and can be used within an object. For example, if there is a method named qux() in the class, which needs to call the baz() and bar() methods in the class, then we can achieve it in the following way:

class MyClass {

public function qux() {
    $this->baz();
    $this->bar();
}
public function baz() { ... }
public function bar() { ... }

}

$this can not only call methods, but also access properties in the class.

Summary

In PHP, we have many ways to call class methods. The most common is to call object methods by instantiating the object. If a method has nothing to do with the object state, then we can define it as a static method to call. In addition, if there is a method in the subclass that conflicts with the parent class, then we can call the method of the parent class through parent::. Finally, if a method in a class needs to use other methods of the class itself, we can do so through $this. By understanding the differences between these calling methods, we can use classes more flexibly and improve code reusability.

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