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func_num_args func_get_arg

Last updated: Sat, 27 Jan 2007

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# func_get_args

(PHP 4, PHP 5)

func_get_args -- Возвращает массив аргументов функции

## Описание

array func_get_args ( void )

Возвращает массив, в котором каждый элемент является соответствующим членом списка аргументов пользовательской функции. func_get_args() генерирует предупреждение при вызове вне определения функции.

`<?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);
?>`

func_get_args() может быть использована совместно с func_num_args() и func_get_arg() для создания функций с переменным количеством аргументов.

add a note User Contributed Notes
func_get_args
rafagd at gmail dot com
13-Feb-2007 08:53
`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.
<?
function dynamicArgs(/*$arg1, $arg2...$argN*/) {
$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)
}`
31-Oct-2006 10:26
`Same idea as below, but this:
foreach( $args as $k => $v ){
switch($k){
case 'a':
$this->a= $v; break;
case 'b':
$this->b= $v; break;
case 'c':
$this->c= $v; break;
}
}
can be shortened to this (as long as all public variables have default values set in their declarations):
foreach( $args as $k=>$v)
if(isset($this->$k)) $this->$k = $v;`
kidekat
01-Oct-2006 06:02
`To pass named arguments in a Perl fashion through class constructors, I use this:
<?php
class Test{
// set class defaults for values not assigned by constructor
public $a = 0;
public $b = 'string';
public $c = array();
public function __construct( $args = array() ) {
// parse tagged arguments in Perl fashion
foreach( $args as $k => $v ){
switch($k){
case 'a':
$this->a= $v; break;
case 'b':
$this->b= $v; break;
case 'c':
$this->c= $v; break;
}
}
}
}
$t = new Test( array( 'b'=>'new value', 'c'=>array(1,'test') ) );
?>
This allows $a to keep its default of 0, while $b gets reassigned to 'new value' and $c becomes the array(1,'test'). The catch is that you add O(n^2) "big-O notation" to the begging of every class constructor which becomes expensive on "larger" classes. While arguments defaults like the following have only O(n) "constant" amount of work.
<?php
public funciton __construct( $a=0, $b='string', $c=array()){ ... }
?>`
bew
31-Mar-2006 07:55
`A more concise way of expressing my idea from the previous post (I'd forgotten about array_slice()):
<?php
function func_get_default_args($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');
?>`
Nathan Ostgard
06-Dec-2005 10:14
`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.`
robert at defore dot st
15-Feb-2005 12:47
`# Another attempt at named args (perl-inspired):
# list_to_assoc('key', 'value', 'key', 'value', ...) =>
# pairs[]
function list_to_assoc() {
$list = func_get_args();
$assoc = array();
while ($list and count($list) > 1) {
$assoc[array_shift($list)] = array_shift($list);
}
if ($list) { $assoc[] = $list[0]; }
return $assoc;
}
# Usage:
function example($required) {
$args = func_get_args(); array_shift($args); # drop 'required'
$rest = list_to_assoc($args);
echo "$required\n" . $rest['comment'];
}
example("This is required...",
'comment', 'this is not.'); # this is like 'comment' => 'this is not'`
T.M.
04-Nov-2004 07:24
`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
?>`
volte6 at drunkduck dot com
30-Sep-2004 02:54
`For those who have a use for a C style enum() function:
//*******************************************
// void enum();
// enumerates constants for unique values guarenteed.
function enum()
{
$i=0;
$ARG_ARR = func_get_args();
if (is_array($ARG_ARR))
{
foreach ($ARG_ARR as $CONSTANT)
{
define ($CONSTANT, ++$i);
}
}
}
// USAGE:
enum(ERR_USER_EXISTS, ERR_OLD_POST);
// etc. etc.
//*******************************************
this can be used for error codes etc.
I deliberately skipped the 0 (zero) define, which could be useful for error checking.`
mark at manngo dot net
23-Mar-2003 11:13
`You can also fake named arguments using eval:
function test()
{ foreach (func_get_args() as $k=>$arg) eval ("\$$arg;");
echo "$a plus $b gives ".($a+$b);
}
test("a=3","b=4");`
fbeyer at clickhand dot de dot noSpamPlease
19-Jan-2002 08:02
`Another way of passing references with a dynamic number of arguments: (This example is limited to 10 arguments)
<?php
define('NULL_ARG', 'DUMMY_ARGUMENT');
function refArg($arg0 = NULL_ARG,
$arg1 = NULL_ARG,
$arg2 = NULL_ARG,
$arg3 = NULL_ARG,
$arg4 = NULL_ARG,
$arg5 = NULL_ARG,
$arg6 = NULL_ARG,
$arg7 = NULL_ARG,
$arg8 = NULL_ARG,
$arg9 = NULL_ARG)
{
for ($args=array(), $i=0; $i < 10; $i++) {
$name = 'arg' . $i;
if ($i < func_num_args()) {
$args[$i] = &$$name;
}
unset($$name, $name);
}
$args[0] = 'Modified.';
}
$test = 'Not modified.<br>';
refArg(&$test);
echo $test; // Prints 'Modified'
?>`
daveNO at ovumSPAMdesign dot com
17-Sep-2001 11:29
`<?php
// How to simulate named parameters in PHP.
// By Dave Benjamin <dave@ovumdesign.com>
// Turns the array returned by func_get_args() into an array of name/value
// pairs that can be processed by extract().
function varargs($args) {
$count = count($args);
for ($i = 0; $i < $count; $i += 2) {
$result[$args[$i]] = $args[$i + 1];
}
return $result;
}
// Example
function test(&$ref1, &$ref2) {
// Default arguments go here.
$foo = "oof";
// Do some magic.
extract(varargs(func_get_args()));
echo nl2br("\n\$var1 = $var1");
echo nl2br("\n\$var2 = $var2");
echo nl2br("\n\$foo = $foo\n\n");
// Modify some variables that were passed by reference.
// Note that func_get_args() doesn't pass references, so they
// need to be explicitly declared in the function definition.
$ref1 = 42;
$ref2 = 84;
}
$a = 5;
$b = 6;
echo nl2br("Before calling test(): \$a = $a\n");
echo nl2br("Before calling test(): \$b = $b\n");
// Try removing the 'foo, "bar"' from the following line.
test($a, $b, var1, "abc", var2, "def", foo, "bar");
echo nl2br("After calling test(): \$a = $a\n");
echo nl2br("After calling test(): \$b = $b\n");
?>`
04-Jun-2001 07:44
`You can pass a variable number of arguments to a function whilst keeping references intact by using an array. The disadvantage of course, is that the called function needs to be aware that it's arguments are in an array.
<?
// Prints "hello mutated world"
function mutator($args=null) {
$n=count($args);
while($i<$n) $args[$i++] = "mutated";
}
$a = "hello";
$b = "strange";
$c = "world";
mutator(array($a, &$b, $c));
echo "$a $b $c";
?>`
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func_num_args func_get_arg

Last updated: Sat, 27 Jan 2007
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