PHP Useful Functions

Functions with Arbitrary Number of Arguments

You may already know that PHP allows you to define functions with optional arguments. But there is also a method for allowing completely arbitrary number of function arguments.
First, here is an example with just optional arguments:

// function with 2 optional arguments
function foo($arg1 = '', $arg2 = '') {

 echo "arg1: $arg1\n";
 echo "arg2: $arg2\n";

}

foo('hello','world');
/* prints:
arg1: hello
arg2: world
*/

foo();
/* prints:
arg1:
arg2:
*/

Now, let’s see how we can build a function that accepts any number of arguments. This time we are going to utilize func_get_args():

// yes, the argument list can be empty
function foo() {

 // returns an array of all passed arguments
 $args = func_get_args();

 foreach ($args as $k => $v) {
  echo "arg".($k+1).": $v\n";
 }

}

foo();
/* prints nothing */

foo('hello');
/* prints
arg1: hello
*/

foo('hello', 'world', 'again');
/* prints
arg1: hello
arg2: world
arg3: again
*/