How to pass variable number of arguments to a PHP function

This is now possible with PHP 5.6.x, using the ... operator (also known as splat operator in some languages):

Example:

function addDateIntervalsToDateTime( DateTime $dt, DateInterval ...$intervals )
{
    foreach ( $intervals as $interval ) {
        $dt->add( $interval );
    }
    return $dt;
}

addDateIntervaslToDateTime( new DateTime, new DateInterval( 'P1D' ), 
        new DateInterval( 'P4D' ), new DateInterval( 'P10D' ) );

In a new Php 5.6, you can use ... operator instead of using func_get_args().

So, using this, you can get all the parameters you pass:

function manyVars(...$params) {
   var_dump($params);
}

Since PHP 5.6, a variable argument list can be specified with the ... operator.

function do_something($first, ...$all_the_others)
{
    var_dump($first);
    var_dump($all_the_others);
}

do_something('this goes in first', 2, 3, 4, 5);

#> string(18) "this goes in first"
#>
#> array(4) {
#>   [0]=>
#>   int(2)
#>   [1]=>
#>   int(3)
#>   [2]=>
#>   int(4)
#>   [3]=>
#>   int(5)
#> }

As you can see, the ... operator collects the variable list of arguments in an array.

If you need to pass the variable arguments to another function, the ... can still help you.

function do_something($first, ...$all_the_others)
{
    do_something_else($first, ...$all_the_others);
    // Which is translated to:
    // do_something_else('this goes in first', 2, 3, 4, 5);
}

Since PHP 7, the variable list of arguments can be forced to be all of the same type too.

function do_something($first, int ...$all_the_others) { /**/ }

For those looking for a way to do this with $object->method:

call_user_func_array(array($object, 'method_name'), $array);

I was successful with this in a construct function that calls a variable method_name with variable parameters.

You can just call it.

function test(){        
     print_r(func_get_args());
}

test("blah");
test("blah","blah");

Output:

Array ( [0] => blah ) Array ( [0] => blah [1] => blah )

I wondered, I couldn't find documentation about the possiblity of using named arguments (since PHP 8) in combination with variable arguments. Because I tried this piece of code and I was surprised, that it actually worked:

function myFunc(...$args) {
    foreach ($args as $key => $arg) {
        echo "Key: $key Arg: $arg <br>";
    }
}
echo myFunc(arg1:"foo", arg2:"bar");

Output:

Key: arg1 Arg: foo
Key: arg2 Arg: bar

In my opinion, this is pretty cool.

I'm surprised nobody here has mentioned simply passing and extracting an array. E.g:

function add($arr){
    extract($arr, EXTR_REFS);
    return $one+$two;
}
$one = 1;
$two = 2;
echo add(compact('one', 'two')); // 3

Of course, this does not provide argument validation. For that, anyone can use my expect function: https://gist.github.com/iautomation/8063fc78e9508ed427d5

Here is a solution using the magic method __invoke

(Available since php 5.3)

class Foo {
    public function __invoke($method=null, $args=[]){
        if($method){
            return call_user_func_array([$this, $method], $args);
        }
        return false;
    }

    public function methodName($arg1, $arg2, $arg3){

    }
}

From inside same class:

$this('methodName', ['arg1', 'arg2', 'arg3']);

From an instance of an object:

$obj = new Foo;
$obj('methodName', ['arg1', 'arg2', 'arg3'])

An old question, an improved answer.

$some_array = array(
    'some-table' => array(
        'where' => array( 
            'column1 = ? and column2 = ?'
        ),
        'parameter-values' => array(1, 2),
        'html-args' => array('id' => 'id', 'name' => ''),
        'variable-arguments' => array(
            array('value-1', 'title-1'),
            array('value-2', 'title-2'),
            array('value-3', 'title-3'),
        )
    )
);

foreach ( $some_array as $table => $args ) {
    $combo = getTableCombo( 
        $table, 
        $args['where'] ?? array(),
        $args['parameter-values'] ?? array(),
        $args['html-args'] ?? array(),
        ...$args['variable-arguments'] ?? array()
    );
}

function getTableCombo( 
    string $table_name, 
    array $where = array(), 
    array $parameter_values = array(),
    array $html_args = array(), 
    array ...$custom_options
    ) {
    //some codes
}

In the above code, We could dynamically call the getTableCombo function with a variable argument named $custom_options

An old question, I know, however, none of the answers here really do a good job of simply answer the question.

I just played around with php and the solution looks like this:

function myFunction($requiredArgument, $optionalArgument = "default"){
   echo $requiredArgument . $optionalArgument;
}

This function can do two things:

If its called with only the required parameter: myFunction("Hi") It will print "Hi default"

But if it is called with the optional parameter: myFunction("Hi","me") It will print "Hi me";

I hope this helps anyone who is looking for this down the road.