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How to implement chain operation in php: 1. Use magic function "__call" combined with "call_user_func" to implement; 2. Use magic function "__call" combined with "call_user_func_array" to implement; 3. Use trim() function to implement.
The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer
There are many strings in php Function, for example, you need 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
Thoughts:First define a string class StringHelper, the constructor assigns value directly, then calls the trim() and strlen() functions in a chain, and uses call_user_func in the called magic function __call() 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('0')->strlen();
Terminal execution script:
php test.php 8
Method 2, use magic function __call combined with call_user_func_array to achieve
<?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 $str->trim('0')->strlen();
Instructions:
array_unshift(array,value1,value2,value3...)
array_unshift()
Function is used to insert new elements into an array. The values of the new array will be inserted at the beginning of the array.
call_user_func()
and call_user_func_array
are both methods of dynamically calling functions. The difference lies in the way parameters are passed.
Method three, do not use the magic function __call, use the trim() function to achieve
Just need to modify _call()
to trim()
Function is enough:
public function trim($t) { $this->value = trim($this->value, $t); return $this; }
The point is to return the $this pointer to facilitate calling the latter function.
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