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A brief discussion on the call_user_func() and call_user_func_array() functions in PHP
A brief discussion on the call_user_func() and call_user_func_array() functions in PHP
This article mainly gives a brief explanation of the functions and usage of the call_user_func() and call_user_func_array() functions in PHP. Friends who are interested can learn about it.
call_user_func: Call a parameter as a callback function
Usage instructions:
call_user_func ( callable $callback [, mixed $parameter [, mixed $... ]] ) : mixed
Parameter description:
First parameter $callback serves as the callback function, and other parameters are parameters of the callback function.
$parameter: The parameter passed in to the callback $callback function. Note that the parameters here cannot be passed by reference.
The following simple examples illustrate the use of call_user_func in different situations:
//先引用，后执行
function _call($call){
echo $call++.'<br/>';
echo $call++.'<br/>';
return $call;
}
$rs = call_user_func('_call',1);
var_dump($rs);
//结果
//1
//2
//int(3)Execute first, then reference
$arg = 1;
call_user_func(function ($call){
echo ++$call.'<br/>';
echo ++$call.'<br/>';
},$arg);
//结果为2，3The callback function does not pass a value, and passes func_get_arg and func_get_args gets parameters
$argOne = 1;
$argTwo = 2;
call_user_func(function (){
//获取第几个参数
$arg = func_get_arg(0);
var_dump($arg);
echo '<br/>';
//获取所有的参数，并以数组的形式返回
$args = func_get_args();
var_dump($args);
//获取参数个数
$argNum = func_num_args();
echo "<br/>";
var_dump($argNum);
},$argOne,$argTwo);
//结果为
int(1)
array(2) { [0]=> int(1) [1]=> int(2) }
int(2)Calling class methods:
There are two forms of calling static methods in a class, and the first parameter of calling a public method can only be an array
class Func{
static public function _One(){
$str = "THE CLASS NAME IS".__CLASS__." AND CLASS STATIC METHOD IS ".__METHOD__;
$argNum = func_num_args();
if($argNum){
$arg = func_get_arg(0);
return $str.' and argument is '.$arg;
}else{
return $str;
}
}
public function _Two($num){
return $num ? $num + 1 : $num;
}
}
echo "<br/>";
//调用类的静态方法
var_dump(call_user_func('Func::_One','one'));
echo '<br/>';
var_dump(call_user_func(['Func','_One']));
$num = 4;
$o = new Func;
//调用类普通方法
$return = call_user_func(array($o,'_Two'),$num);
echo '<br/>';
var_dump($return);
结果：
string(79) "THE CLASS NAME ISFunc AND CLASS STATIC METHOD IS Func::_One and argument is one"
string(59) "THE CLASS NAME ISFunc AND CLASS STATIC METHOD IS Func::_One"
int(5)When calling a class with a namespace, the usage of call_user_func is the same as above
//调用静态方法 call_user_func(array(__NAMESPACE__.'\StaticDemo','_One'),100); call_user_func('App\StaticDemo::_One',200); //调用public方法 call_user_func(array($obj,'_Two'),2,3,4);
Finally:
Similar to the call_user_func function, there is call_user_func_array, the function of call_user_func_array is the same as call_user_func The function is the same,
The difference is that call_user_func uses a callback function to process characters, while call_user_func_array uses a callback function to process arrays, which means that the second parameter of call_user_func_array can only be an array.
Related tutorials: PHP video tutorial
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