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(PHP 4, PHP 5, PHP 7)
func_get_args — 返回一个包含函数参数列表的数组
获取函数参数列表的数组。
该函数可以配合 func_get_arg() 和 func_num_args() 一起使用,从而使得用户自定义函数可以接受自定义个数的参数列表。
返回一个数组,其中每个元素都是目前用户自定义函数的参数列表的相应元素的副本。
版本 | 说明 |
---|---|
5.3.0 | 该函数可以在参数列表中使用。 |
5.3.0 |
If this function is called from the outermost scope of a file
which has been included by calling include
or require from within a function in the
calling file, it now generates a warning and returns FALSE .
(不知道如何翻译跟好,直接参考例2即可明白)
|
在用户自定义函数外调用则会出现错误警告。
Example #1 func_get_args() 例子
<?php
function foo ()
{
$numargs = func_num_args ();
echo "Number of arguments: $numargs <br />\n" ;
if ( $numargs >= 2 ) {
echo "Second argument is: " . func_get_arg ( 1 ) . "<br />\n" ;
}
$arg_list = func_get_args ();
for ( $i = 0 ; $i < $numargs ; $i ++) {
echo "Argument $i is: " . $arg_list [ $i ] . "<br />\n" ;
}
}
foo ( 1 , 2 , 3 );
?>
以上例程会输出:
Number of arguments: 3<br /> Second argument is: 2<br /> Argument 0 is: 1<br /> Argument 1 is: 2<br /> Argument 2 is: 3<br />
Example #2 PHP 5.3 前后使用 func_get_args() 在的对比
test.php
<?php
function foo () {
include './fga.inc' ;
}
foo ( 'First arg' , 'Second arg' );
?>
fga.inc
<?php
$args = func_get_args ();
var_export ( $args );
?>
PHP 5.3 版本之前的输出:
array ( 0 => 'First arg', 1 => 'Second arg', )
PHP 5.3 和之后的版本的输出:
Warning: func_get_args(): Called from the global scope - no function context in /home/torben/Desktop/code/ml/fga.inc on line 3 false
Example #3 func_get_args() example of byref and byval arguments
<?php
function byVal ( $arg ) {
echo 'As passed : ' , var_export ( func_get_args ()), PHP_EOL ;
$arg = 'baz' ;
echo 'After change : ' , var_export ( func_get_args ()), PHP_EOL ;
}
function byRef (& $arg ) {
echo 'As passed : ' , var_export ( func_get_args ()), PHP_EOL ;
$arg = 'baz' ;
echo 'After change : ' , var_export ( func_get_args ()), PHP_EOL ;
}
$arg = 'bar' ;
byVal ( $arg );
byRef ( $arg );
?>
以上例程会输出:
Note:
因为函数依赖于当前作用域以确定参数的细节,所以在 5.3.0 以前的版本中不能用作函数的参数。如必须传递此值时,可将结果赋与一个变量,然后用此变量进行传递。
Note:
如果参数以引用方式传递,函数对该参数的任何改变将在函数返回后保留。
Note: 该函数仅仅是返回传递参数的一个副本,并且不包含没有传入的默认参数。
[#1] dev at mp3addict dot pw [2014-03-09 07:05:35]
This function is as printf() but only calls printf() when the debug_enabled global variable is set to TRUE. Because by this way, you can use debug() instead of echo | printf() and set debug_enabled to false after checking and submitting work into production.
cheers;
function debug () {
if ($GLOBALS['debug_enabled'] == true) {
$args = func_get_args();
$fmt = $args[0];
$printf_args = '';
for ($i = 1; $i < count($args); $i++) {
$printf_args .= ",\"{$args[$i]}\"";
}
eval("printf(\"{$fmt}\"{$printf_args});");
}
}
[#2] maarten at ba dot be [2012-09-13 11:58:56]
it seems that this function only returns a copy and loses it's byref information, use this dirty non-efficient workaround instead:
at the moment of writing it currently returns all of them as references, instead of only the ones who are passed that way...
<?php
function func_get_args_byref() {
$trace = debug_backtrace();
return $trace[1]['args'];
}
?>
[#3] OpenTechnologist [2011-12-30 19:54:08]
please note that optional parameters are not seen/passed by func_get_args(), as well as func_get_arg().
ex:
<?php
function testfunc($optional = 'this argument is optional..') {
$args = func_get_args();
var_dump($args);
echo $optional;
}
?>
test case #1:
testfunc('argument no longer optional..');
result for #1:
array(1) {
[0]=> string(20) "argument no longer optional.."
}
argument no longer optional..
test case #2:
testfunc('argument no longer optional..','this is an extra argument');
result for #2:
array(2) {
[0]=> string(29) "argument no longer optional.."
[1]=> string(25) "this is an extra argument"
}
argument no longer optional..
test case #3: -- RESULTS IN AN EMPTY ARRAY
testfunc();
result for #3:
array(0) {
}
this argument is optional..
[#4] red [2011-10-13 13:16:45]
I had to pass variable length arguments from one function to another. It seems the only way of doing this is to use call_user_func_array.
<?php
function query(){
$query = call_user_func_array('replaceAndClean', func_get_args());
$result = mysql_query($query);
return $result;
}
function replaceAndClean(){
$args = func_get_args();
if(count($args) == 1){
return $args[0];
}
$query = array_shift($args);
return vsprintf($query, array_map('mysql_real_escape_string', $args));
}
?>
Example:
<?php
// unsave call
query("SELECT FROM foo where bar='".$_POST['bar']."'");
// save call
query("SELECT FROM foo where bar='%d'", $_POST['bar']);
?>
[#5] pBakhuis at Gmail dot com [2011-10-05 05:30:13]
Please note that you can't use this for recursive functions as you can't pass the parameters to the function again as then they'll be in the form of an array.
[#6] mulllhausen [2011-04-05 19:49:06]
i use this structure a lot for debugging. i always place the call to 'debugfunc' at the start of any function which i want to debug. the square brackets in the echod output are useful to see if there is accidental whitespace within string variables passed to anyfunc. if anyone can suggest a better way of passing the names of the arguments to debugfunc i would appreciate it. as it is works fine, but its not very universal...
<?php
anyfunc('val1','val2','val3');
function anyfunc($arg1, $arg2, $arg3)
{
debugfunc(__FUNCTION__, '$arg1, $arg2, $arg3', func_get_args());
}
function debugfunc($name, $arg_names, $arg_vals)
{
echo "begin function [$name]. ";
$arg_names_array = explode(',', $arg_names);
foreach($arg_names_array as $k => $v)
{
$v = trim($v);
echo "$v: [$arg_vals[$k]] ";
}
echo "\n";
}
//output:
//begin function [anyfunc]. $arg1: [val1] $arg2: [val2] $arg3: [val3]
?>
[#7] mitko at edabg dot com [2009-04-06 03:48:45]
<?php
class foo {
var $bar = "default bar";
function foo() {
// func_get_args returns copy of arguments
// $args = func_get_args();
// debug_backtrace returns arguments by reference
$stack = debug_backtrace();
$args = array();
if (isset($stack[0]["args"]))
for($i=0; $i < count($stack[0]["args"]); $i++)
$args[$i] = & $stack[0]["args"][$i];
call_user_func_array(array(&$this, 'bar'), $args);
}
function bar($bar = NULL) {
if (isset($bar))
$this->bar = & $bar;
}
}
$global_bar = "bar global";
$foo = & new foo();
echo "foo->bar: ".$foo->bar."</br>\n";
$foo->bar = "new bar";
echo "global_bar: ".$global_bar."</br>\n";
$foo = & new foo(&$global_bar);
echo "foo->bar: ".$foo->bar."</br>\n";
$foo->bar = "new bar";
echo "global_bar: ".$global_bar."</br>\n";
?>
[#8] Oto Brglez [2009-03-12 06:18:44]
How to create simple sum function that can sum N arguments. Like this:
<?php
function sum(){
$s=0;
foreach(func_get_args() as $a) $s+= is_numeric($a)?$a:0;
return $s;
};
print sum(1,2,3,4,5,6); // will return 21
print sum(3,2,1); // will return 6
print sum(false,array(),5,5); // will return 10
?>
[#9] anderson at francotecnologia dot com [2008-08-26 23:25:58]
How to create a polymorphic/"overloaded" function
<?php
function select()
{
$t = '';
$args = func_get_args();
foreach ($args as &$a) {
$t .= gettype($a) . '|';
$a = mysql_real_escape_string($a);
}
if ($t != '') {
$t = substr($t, 0, - 1);
}
$sql = '';
switch ($t) {
case 'integer':
// search by ID
$sql = "id = {$args[0]}";
break;
case 'string':
// search by name
$sql = "name LIKE '%{$args[0]}%'";
break;
case 'string|integer':
// search by name AND status
$sql = "name LIKE '%{$args[0]}%' AND status = {$args[1]}";
break;
case 'string|integer|integer':
// search by name with limit
$sql = "name LIKE '%{$args[0]}%' LIMIT {$args[1]},{$args[2]}";
break;
default:
// :P
$sql = '1 = 2';
}
return mysql_query('SELECT * FROM table WHERE ' . $sql);
}
$res = select(29); // by ID
$res = select('Anderson'); // by name
$res = select('Anderson', 1); // by name and status
$res = select('Anderson', 0, 5); // by name with limit
?>
[#10] kangaroo232002 at yahoo dot co dot uk [2008-08-26 14:25:23]
Instead of having to define your arg list twice, and keeping to the good style of initialising your variables in the head of your class, you can use (PHP5):
<?php
class myclass {
public $value = null;
public $key = null;
public $column = null;
public $table = null;
public function __construct() {
$vars = get_class_vars();
for($i=0; $i<func_num_args();$i++) {
$this->${$vars[$i]}=func_get_arg($i);
}
}
}
?>
which should allow you to set variables while retaining their default values if they are not set (in this case, null), without having to mess around with functions to retain default values so is much neater (just don't change the order you declare your vars!)
<?php
//usage
$c = new myclass("value", "tablekey", "tablecol", "table");
echo $c->key;
//prints 'tablekey'
?>
[#11] Anonymous [2008-01-28 20:11:49]
I use the following concept for quick "plugin" of multiple argument support.
<?php
function increment($n) {
$p = func_get_args();
if (count($p) > 1) {
return array_map(__FUNCTION__, $p);
}
$n =& $p[0];
return ++$n;
}
list($two, $three, $four) = increment(1,2,3);
?>
[#12] tristan dot colombo at laposte dot net [2007-10-18 01:03:28]
In order to use the function 'func_get_args()' to instanciate differents type of objects, you must use the Reflection API.
By example, we have two different classes and we want to have an unique function (using an unfixed number of parameters) to create the objects. We create two classes 'a' and 'b' where constructors accept different numbers of arguments.
Class a (class/a.class.php):
<?php
include_once 'a.class.php';
class b extends a
{
private $param3;
public function __construct($a, $b, $c)
{
$this->param1 = $a;
$this->param2 = $b;
$this->param3 = $c;
}
public function display()
{
echo $this->param1 . ', ' . $this->param2 . ' and ' . $this->param3 . '!<br />';
}
}
?>
Class b (class/b.class.php):
<?php
class a
{
private $param1;
private $param2;
public function __construct($a, $b)
{
$this->param1 = $a;
$this->param2 = $b;
}
public function display()
{
echo $this->param1 . ' and ' . $this->param2 . '<br />';
}
}
?>
Main program :
<?php
function classFactory()
{
// Retrieve arguments list
$_args = func_get_args();
// Delete the first argument which is the class name
$_className = array_shift($_args);
// Include the requested class
include_once 'class/' . $_className . '.class.php';
// Create Reflection object
// See : http://www.php.net/manual/en/language.oop5.reflection.php
$_reflection = new ReflectionClass($_className);
// Use the Reflection API
return $_reflection->newInstanceArgs($_args);
}
$a = classFactory('a', 'hello', 'world');
$b = classFactory('b', 'that\'s', 'all', 'folks');
$a->display();
$b->display();
?>
[#13] Sinured [2007-08-20 05:38:35]
It may seem obvious, but if you want your variadic function to at least require one parameter, you can do this instead of checking func_num_args() == 0, which I've seen often:
<?php
function variadic($dummy) {
$args = func_get_args();
foreach ($args as $arg) {
echo "$arg<br />\n";
}
}
?>
func_get_args() fetches ALL passed parameters, not only those that weren't copied to a local variable.
[#14] ario [a] mail [dot] utexas [dot] edu [2007-05-07 14:50:58]
"Because this function depends on the current scope to determine parameter details, it cannot be used as a function parameter. If you must pass this value, assign the results to a variable, and pass the variable."
This means that the following code generates an error:
<?php
function foo($list)
{
echo implode(', ', $list);
}
function foo2()
{
foo(func_get_args());
}
foo2(1, 2, 3);
?>
However, you can easily get around this by doing the following:
<?php
function foo($list)
{
echo implode(', ', $list);
}
function foo2()
{
foo($args = func_get_args());
}
foo2(1, 2, 3);
?>
This captures the context from foo2(), making this legal. You get the expected output:
"1, 2, 3"
[#15] rafagd at gmail dot com [2007-02-13 08:53:08]
Sometimes, you may need to dynamic set and get of args...
This function merge array args, so you can dynamic set some args by sending an array arg.
<?php
function dynamicArgs() {
$args = func_get_args(); $num = func_num_args();
for ($i = 1; $i < $num; $i++) {
$args[0] = array_merge((array) $args[0], (array) $args[$i]);
}
return $args[0];
}
var_dump(dynamicArgs('a',array('b','c'),'d',1);
?>
This should output like:
array(5) {
[0]=>
string(1) "a"
[1]=>
string(1) "b"
[2]=>
string(1) "c"
[3]=>
string(1) "d"
[4]=>
int(1)
}
[#16] bew [2006-03-31 07:55:18]
A more concise way of expressing my idea from the previous post (I'd forgotten about array_slice()):
<?php
function func_get_default_args($a) {
$args = array_slice(func_get_args(), 1);
return array_merge($args, array_slice($a, sizeof($args)));
}
function foo($a = 1, $b = 2, $c = 3) {
print_r(func_get_default_args(func_get_args(), $a, $b, $c));
}
// prints: Array ( [0] => a [1] => b [2] => 3 )
foo('a', 'b');
?>
[#17] Nathan Ostgard [2005-12-06 10:14:17]
If you're using PHP5, the variable number of argument functions all return the objects by reference - and not a copy of the object, as this leads you to believe.
[#18] T.M. [2004-11-04 07:24:33]
Simple function to calculate average value using dynamic arguments:
<?php
function average(){
return array_sum(func_get_args())/func_num_args();
}
print average(10, 15, 20, 25); // 17.5
?>
[#19] volte6 at drunkduck dot com [2004-09-30 14:54:10]
For those who have a use for a C style enum() function:
<?php
/
function printTag() {
$numArgs = func_num_args();
if ($numArgs < 1) die("printTag given no arguments");
echo "<" . func_get_arg(0);
for ($i = 1; $i < $numArgs; $i+=2) {
echo " " . func_get_arg($i);
if ($i+1 < $numArgs)
echo "=\"" . func_get_arg($i+1) . "\"";
}
echo ">";
}
function printTagNL() {
$args = func_get_args();
call_user_func_array("printTag", $args);
echo "\n";
}
printTagNL("input", "type", "hidden", "name", "SORTORDER", "value", $columnNo);
?>
[#6] thalis at NOSPAMcs dot pitt dot edu [2002-03-29 12:05:31]
The idea of func_get_args() is to construct functions of variable number of parameters like
<?php
function var_param_func(){
if(func_num_args()==0){
//do one thing
}
if(func_num_args()==1)
//do another thing
//get the args with func_get_args()
}
}
?>