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There are many string functions in php. For example, you need to filter the spaces at the end of the 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 I write like the following?
$str->trim()->strlen()
The following are three ways to achieve it:
__call
combined with call_user_func
to achieve Thought: First define a string class StringHelper
, the constructor directly assigns value, and then chain calls trim()
and strlen()
function, by using 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
__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 $str->trim('0')->strlen();
Instructions:
array_unshift(array,value1,value2,value3...)
array_unshift()
Function is used to insert new elements into the array. The values of the new array will be inserted at the beginning of the array.
call_user_func()
and call_user_func_array
are both methods of dynamically calling functions. The difference lies in the way parameters are passed.
__call
to achieve Just modify _call()
to trim()
Just use a function:
public function trim($t) { $this->value = trim($this->value, $t); return $this; }
The point is to return the $this pointer to facilitate calling the latter function.
There are many string functions in php. For example, you need to filter the spaces at the end of the string first, and then find its length. The general way of writing is:
strlen(trim($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 three ways to achieve it:
__call
combined with call_user_func
to achieve Thought: First define a string class StringHelper
, the constructor directly assigns value, and then chain calls trim()
and strlen()
function, by using 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
__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 $str->trim('0')->strlen();
Instructions:
array_unshift(array,value1,value2,value3...)
array_unshift()
Function is used to insert new elements into the array. The values of the new array will be inserted at the beginning of the array.
call_user_func()
and call_user_func_array
are both methods of dynamically calling functions. The difference lies in the way parameters are passed.
__call
to achieve Just modify _call()
to trim()
Just use a function:
public function trim($t) { $this->value = trim($this->value, $t); return $this; }
The key point is to return the $this pointer to facilitate calling the latter function.
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