There are several ways to implement chain operations in PHP

The three methods of chain operations using PHP are to use magic function call combined with call_user_func to implement, to use magic function call combined with call_user_func_array to implement and without using magic function call.

There are many stringsfunctions in php. For example, to filter the spaces at the end of a string first, and then find its length. The general way of writing is:

strlen(trim($str))

If you want to implement a chain operation similar to that in js, for example, how should you write it like the following?

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

The following are implemented in three ways:

Method 1. Use the magic function call combined with call_user_func to achieve

Thought: First define a string class StringHelper, constructor directly assign value, and then call the trim() and strlen() functions in a chain, by calling the magic function call() Use call_user_func to handle the calling relationship. 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(&#39;0&#39;)->strlen();

Terminal execution script:

php test.php

Method 2. Use The magic function call is combined with call_user_func_array to implement

<?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(&#39;0&#39;)->strlen();

Description:

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

array_unshift() function is used to insert new elements into an array. The values ​​of the new array will be inserted at the beginning of the array.

call_user_func() and call_user_func_array are both methods of dynamically calling functions. The difference lies in the way parameters are passed.

Method three, do not use the magic function call to achieve

Just modify _call() to trim() function:

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

The key point is to return $this Pointer to facilitate calling the latter function.

Method three, do not use the magic function call to achieve

Just modify _call() to trim() function:

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

The key point is to return $this Pointer to facilitate calling the latter function.

# I believe you have mastered the methods after reading these cases. For more exciting information, please pay attention to other related articles on the php Chinese website!

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