Introduction to the usage of $this in php

In php, we usually declare a class first, and then use this class to instantiate objects!

Usage:

$this means the specific object after instantiation.

$this->Indicates using the attributes or methods of this class within the class itself.

The ‘->’ symbol is the “infix dereference operator”. In other words, it is a method that calls a subroutine whose parameters are passed by reference (among other things, of course). As we mentioned above, when calling PHP functions, most parameters are passed by reference.

For example, we declare a User class! It only contains one attribute $name

<?php
class User
{
   public $_name;
}
?>

Now, we add a method to the User class.

<?php
class User
{
      public $name;
      function getName()
      {
             echo $this->name;
      }
}
//如何使用呢？
$user1 = new User();
$user1->name = &#39;张三&#39;;
$user1->getName();        //这里就会输出张三！
$user2 = new User();
$user2->name = &#39;李四&#39;;   
$user2->getName();       //这里会输出李四！
?>

Two User objects are created above. They are $user1 and $user2 respectively.

When $user1->getName() is called, the code in the User class above echo $this->name ; is equivalent to echo $user1->name;

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