func_get_args
If you want to pass the parameters on intact to another function, use func_get_args and call_user_func_array (careful - this one is only available in recent PHP versions). For example:
<?php
/* Print an HTML tag. This accepts a variable number of arguments:
the first should be the name of the tag, followed by pairs of
arguments that describe keys and values. The values are printed
with surrounding double quote characters. */
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 ">";
}
/* Print an HTML tag with a newline on the end */
function printTagNL() {
$args = func_get_args();
call_user_func_array("printTag", $args);
echo "\n";
}
printTagNL("input", "type", "hidden", "name", "SORTORDER", "value", $columnNo);
?>
func_num_args
(PHP 4, PHP 5)
func_num_args — Devuelve el número de argumentos pasados a la función
Descripción
int func_num_args
( void
)
Obtiene el número de argumentos pasados a la función.
Esta función se puede usar junto con func_get_arg() y func_get_args() para permitir a las funciones defenidas por es usuario aceptar listas de argumentos de longitud variable.
Valores devueltos
Devuelve el número de argumentos pasados a la función actual definida por el usuario.
Historial de cambios
| Versión | Descripción |
|---|---|
| 5.3.0 | Esta función ahora se puede usar en listas de parámetros. |
| 5.3.0 | Si esta función es llamada desde el ámbito último de un fichero que ha sido incluido mediante una llamada a include o require desde dentro de una función en el fichero de llamada, ahora genera una advertencia y devuelve -1. |
Errores/Excepciones
Genera una advertencia si se llama desde fuera de una función definida por el usuario.
Ejemplos
Ejemplo #1 Ejemplo de func_num_args()
<?php
function foo()
{
$númargs = func_num_args();
echo "Número de argumentos: $númargs\n";
}
foo(1, 2, 3);
?>
El resultado del ejemplo sería:
Número de argumentos: 3
Ejemplo #2 Ejemplo de func_num_args() antes y después de PHP 5.3
prueba.php
<?php
function foo() {
include './fna.php';
}
foo('Primer argumento', 'Segundo argumento');
?>
fna.php
<?php
$núm_args = func_num_args();
var_export($núm_args);
?>
Salida antes de PHP 5.3:
2
La salida en PHP 5.3 y posterior será algo similar a:
Warning: func_num_args(): Called from the global scope - no function context in /home/torben/Desktop/code/ml/fna.inc on line 3 -1
Notas
Nota:
Como esta función depende del ámbito actual para determinar los detalles del parámetro, no puede ser usada como parámetro de función en versiones anteriores a 5.3.0. Si se require pasar el valor, los resultados deben ser asignados a una variable y esta variable debería pasarse como parámetro.
Ver también
- func_get_arg() - Devuelve un elemento de una lista de argumentos
- func_get_args() - Devuelve una matriz que se compone de una lista de argumentos de función
- ReflectionFunctionAbstract::getNumberOfParameters() - Obtiene el número total de parámetros
add a note
User Contributed Notes
func_num_args - [9 notes]
ashley at dcs dot warwick dot ac dot uk ¶
11 years ago
luisguillermo dot quevedovelez at gmail dot com ¶
1 year ago
I had defined a function function_name(){ ...} as a drupal callback.
I try to get how many params where passed
I got a Error and my Site falls down
I've replaced func_get_args() instead func_num_args() and my Site was restored.
I conclude you can not use func_num_args() in callbacks.
Hope it helps.
andy at arakka dot co dot th ¶
8 years ago
func_num_args() can be used in conjunction with named arguments, also. For example:
<?php
function DebugShow( $label, $value ) {
echo "# " . $label ;
if ( func_num_args() > 1 ) echo " = " . $value ;
echo "<br>";
}
?>
Dennis Robinson from basnetworks dot net ¶
3 years ago
This function comes in handy, and I believe is the only solution, when you have an optional parameter that can take any type of data.
For example:
<?php
// $data can be of any type, including null
function my_function($name, $data = null)
{
if ($data !== null)
{
// Do something with $data
// If you call my_function('something'), this WILL NOT be reached
// If you call my_function('something', null), this WILL NOT be reached
}
}
?>
The problem with the above function is that you will never be able to use null as the value for $data. To fix this, use func_num_args() like so:
<?php
// $data can be of any type, including null
function my_function($name, $data = null)
{
if (func_num_args() >= 2)
{
// Do something with $data
// If you call my_function('something'), this WILL NOT be reached
// If you call my_function('something', null), this WILL be reached
}
}
?>
This solution works because func_num_args() reports exactly how many arguments were passed when the function was called. It does not take into account when default argument values are used.
padron at aaargh dot com dot br ¶
6 years ago
func_num_args(), func_get_args() and func_get_arg() can be very useful to emulate overloading in PHP.
Suppose you have a class to add a user in a system, and that you want to allow 2 ways of doing it. The first way would be passing an array with all the user info in it, and the second way would be passing each user attribute as a single argument.
<?php
class Test {
function insertUser() {
// gets the number of parameters
$numArgs = func_num_args();
// make decisions based on the arguments number
if ($numArgs == 1) {
// if it's only one argument, we suppose that it is an array with user info
// gets the first argument
$user = func_get_arg(0);
// checks if it really is an array
if (is_array($user)) {
// here you should check if the array contains all necessary fields
// adds the user
echo "User added.<br/>";
echo "ID: " . $user["id"] . "<br/>";
echo "NAME: " . $user["name"] . "<br/>";
echo "EMAIL: " . $user["email"] . "<br/>";
} else {
// generates an error if argument is not an array
echo "Argument is not an array: " . $user . ".<br/>";
}
} else if ($numArgs == 3) {
// if the function receives 3 arguments, we assume that they
// are 'id', 'name' and 'email' respectively
// inserts the user into the system
echo "User added.<br/>";
echo "ID: " . func_get_arg(0) . "<br/>";
echo "NAME: " . func_get_arg(1) . "<br/>";
echo "EMAIL: " . func_get_arg(2) . "<br/>";
} else {
// if the number of arguments is different from 1 and 3
// an error will be generated
echo "Wrong argument number.<br/>";
echo "Arguments received: " . func_num_args();
}
}
}
// creates an Test object
$objTest = new Teste();
// inserts an user passing an array with all his info
$objTest->insertUser(array("id" => 1, "name" => "George W. Bush", "email" => "jackass@whitehouse.gov"));
echo "<br/>";
// inserts an user providing each attribute as a single argument
$objTest->insertUser(2, "Vicente Fox", "iloveusa@disney.com");
echo "<br/>";
// this will generate an error, because only 2 arguments were passed
$objTest->insertUser(3, "Tony Blair");
?>
jared at ws-db dot com ¶
7 years ago
Just a note for anyone wondering. This function doesn't include params that have a default value, unless you pass one in to overwrite the default param value. Not sure if that makes sense, so here's an example:
<?php
function helloWorld($ArgA, $ArgB="HelloWorld!") {
return func_num_args();
}
// The following will return 1
$Returns1 = helloWorld("HelloWorld!");
// The following will return 2
$Returns2 = helloWorld("HelloWorld!", "HowdyWorld!");
?>
thalis at NOSPAMcs dot pitt dot edu ¶
11 years ago
The idea of func_get_args() is to construct functions of variable number of parameters like
<?php
function var_param_func(){
if(func_num_args()==0){
//do one thing
}
if(func_num_args()==1)
//do another thing
//get the args with func_get_args()
}
}
?>
neelam_ab2003 at yahoo dot co dot in ¶
7 years ago
Just adding a note to JARED's Note.
func_num_args() works if and only if called from within a function definition BECAUSE it calculates the number of arguments sent while function calling. That is why it gives
'1' in helloWorld("HelloWorld!") and '2' in helloWorld("HelloWorld!", "HowdyWorld!") - There is nothing to do with DEFAULT args.
If you call the same function as helloWorld(); "No args passed"
It will give a warning for wrong function call ("Warning: Missing argument 1 for helloWorld()") and the result of func_num_args() will be '0'.
friz at godshell dot com ¶
7 years ago
This function comes in extremely handy in OO Classes. My focus is currently PHP 4, but this technique probably works just as well in PHP 5.
<?php
Class foo {
// constructor, other methods, etc
function somedata($somedata = '') {
if (func_num_args() > 0) {
$this->somedata = $somedata;
}
return $this->somedata;
}
}
?>
This allows for a default value to be set, while not requiring the parameter. (Yes, I'm aware that it only warns when you do, but I think this is a little cleaner)