When I looked at UCenter, there was a function call_user_func. I was puzzled because I thought it was a function defined by myself, but I couldn’t find it anywhere. After searching on Baidu, I found out that call_user_func is Built-in function
The call_user_func function is similar to a special method of calling a function. The method of use is as follows:
function a($b,$c) { echo $b; echo $c; } call_user_func('a', "111","222"); call_user_func('a', "333","444"); //显示 111 222 333 444
It is strange to call the method inside the class, but it is used It is an array. I don’t know how the developers considered it. Of course, new is omitted, which is also full of novelty:
class a { function b($c) { echo $c; } } call_user_func(array("a", "b"),"111"); //显示 111
The call_user_func_array function is very similar to call_user_func, except that the parameters are passed in a different way. Make the structure of parameters clearer:
function a($b, $c) { echo $b; echo $c; } call_user_func_array('a', array("111", "222")); //显示 111 222
The call_user_func_array function can also call methods inside the class
Class ClassA { function bc($b, $c) { $bc = $b + $c; echo $bc; } } call_user_func_array(array('ClassA','bc'), array("111", "222")); //显示 333
Both the call_user_func function and the call_user_func_array function support references, which makes them and Ordinary function calls tend to have consistent functions:
function a(&$b) { $b++; } $c = 0; call_user_func('a', &$c); echo $c;//显示 1 call_user_func_array('a', array(&$c)); echo $c;//显示 2
Simple usage of call_user_func_array in php
<?php function foobar($arg, $arg2) { echo FUNCTION, " got $arg and $arg2\n"; } class foo { function bar($arg, $arg2) { echo METHOD, " got $arg and $arg2\n"; } } // Call the foobar() function with 2 arguments call_user_func_array("foobar", array("one", "two")); // Call the $foo->bar() method with 2 arguments $foo = new foo; call_user_func_array(array($foo, "bar"), array("three", "four")); ?>
The output of the above routine is similar to:
foobar got one and two
foo::bar got three and four
Example #2 call_user_func_array() using namespace name
<?php namespace Foobar; class Foo { static public function test($name) { print "Hello {$name}!\n"; } } // As of PHP 5.3.0 call_user_func_array(NAMESPACE .'\Foo::test', array('Hannes')); // As of PHP 5.3.0 call_user_func_array(array(NAMESPACE .'\Foo', 'test'), array('Philip')); ?>
The output of the above routine is similar to:
Hello Hannes!
Hello Philip!
Example #3 Using lambda function
<?php $func = function($arg1, $arg2) { return $arg1 * $arg2; }; var_dump(call_user_func_array($func, array(2, 4))); /* As of PHP 5.3.0 */ ?>
The above routine will output:
int(8)
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