Detailed Explanation of Three Methods of Realizing Chain Operation in PHP

In this paper, three methods of chain operation in PHP are described by examples. Share it for your reference, as follows:

There are many string functions in php, such as filtering the space at the end of the string first, and then finding its length. The general writing method is:

strlen(trim($str))

What should I write if I want to implement a chain operation similar to that in js, such as the following?

$str->trim()->strlen()

The following are implemented in three ways:

Method 1. Use the magic function __call combined with call_user_func

Idea: Firstly, a string class StringHelper is defined, and the constructor directly assigns value, then the functions trim () and strlen () are called in a chain, and the calling relationship is handled by using call_user_func in the called magic function __call (). The implementation is as follows:

<?php
class StringHelper 
{
  private $value;
  function __construct($value)
  {
    $this->value = $value;
  }
  function __call($function, $args){
    $this->value = call_user_func($function, $this->value, $args[0]);
    return $this;
  }
  function strlen() {
    return strlen($this->value);
  }
}
$str = new StringHelper(" sd f 0");
echo $str->trim('0')->strlen();

Terminal execution script:

php test.php 
8

Method 2. Use the magic function __call in combination with call_user_func_array

<?php
class StringHelper 
{
  private $value;
  function __construct($value)
  {
    $this->value = $value;
  }
  function __call($function, $args){
    array_unshift($args, $this->value);
    $this->value = call_user_func_array($function, $args);
    return $this;
  }
  function strlen() {
    return strlen($this->value);
  }
}
$str = new StringHelper(" sd f 0");
echo $str->trim('0')->strlen();

Description:

array_unshift(array,value1,value2,value3...)

array_unshift() Function is used to insert a new element into an array. The value of the new array will be inserted at the beginning of the array.

call_user_func() And call_user_func_array They are all methods of calling functions dynamically, and the difference lies in the different ways of passing parameters.

Method 3. Do not use the magic function __call to implement

Just need to modify _call() For trim() Function can:

public function trim($t)
{
  $this->value = trim($this->value, $t);
  return $this;
}

The key point is to return the $this pointer, which is convenient for calling the latter function.

For more readers interested in PHP related content, please check the topics on this site: "Introduction to php Object-Oriented Programming", "Encyclopedia of PHP Array (Array) Operation Skills", "Introduction to PHP Basic Grammar", "Summary of PHP Operation and Operator Usage", "Summary of php String (string) Usage", "Introduction to php+mysql Database Operation" and "Summary of php Common Database Operation Skills"

I hope this article is helpful to everyone's PHP programming.