How to call object method in php

PHP (Hypertext Preprocessor) is a popular open source server-side scripting language that can run on a Web server and is used to create dynamic web content for websites. In PHP, calling methods can be object methods or ordinary methods. The following uses object methods as an example to introduce how to call methods in PHP.

1. Create an object

In PHP, when calling an object method, you first need to create an object. Object is a special data type defined by a class that encapsulates data and methods. To create an object, you first need to define a class.

You can use the class keyword to define a class, followed by the class name. Class names must be unique, if the class name is the same as another defined class name, an error will occur. In a class definition, you can define properties and methods.

class MyClass {
    // 定义属性
    public $name;
    public $age;
    // 定义方法
    public function sayHello() {
        echo "Hello!";
    }
}

After defining the class, you can create an object through the new keyword.

$object = new MyClass();

$object here is an object variable, which stores an instance of the MyClass class.

2. Call object methods

Once the object is created, the object method can be called through the object variable. The syntax for calling object methods is: $object->methodName(). Among them, $object is the object variable and methodName is the method name. Parameters can be passed in parentheses.

$object->sayHello(); // 输出 Hello!

When calling object methods, you need to pay attention to the following points:

1. Object variables must be declared and initialized before use.
2. Methods must be defined in the class before they can be called.
3. The method name must be the same as the method name defined in the class and is case-sensitive.
4. Method calls can have parameters or not.

3. Access object properties

In addition to calling object methods, you can also access object properties in PHP. Object properties are variables defined in a class that store state information about the object. Object properties can be declared using the keywords public, protected, or private, indicating different access rights.

1. Public properties: Public properties that can be accessed both outside and inside the class.
2. protected attribute: Protected attribute, which can only be accessed inside the class and subclasses.
3. Private attribute: Private attribute, which can only be accessed inside the class.

The syntax for accessing object properties is: $object->propertyName. Among them, $object is the object variable and propertyName is the property name.

class MyClass {
    // 定义属性
    public $name;
    protected $age;
    private $gender;
    // 定义方法
    public function setAge($newAge) {
        $this->age = $newAge;
    }
    public function getAge() {
        return $this->age;
    }
}
$object = new MyClass();
$object->name = 'Tom';
$object->setAge(20);
echo $object->name; // 输出 Tom
echo $object->getAge(); // 输出 20

When accessing object properties, you need to pay attention to the following points:

1. Object variables must be declared and initialized before use.
2. Attributes must be defined in the class before they can be accessed.
3. The attribute name must be the same as the attribute name defined in the class, and is case-sensitive.
4. Inside the class, you can use the keyword $this to refer to the current object.
5. When accessing properties, you need to pay attention to the access permissions of the properties.

• 4. Summary

This article introduces how to call object methods in PHP. First, you need to Create an object and then use object variables and method names to call object methods. The article also introduces how to access object attributes. Attributes with different access permissions have different access methods. By studying this article, readers can learn how to use object methods for programming in PHP and improve code reusability and maintainability.

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