PHP可变长函数方法介绍

示例：

<?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);
?>

Number of arguments: 3
Second argument is: 2
Argument 0 is: 1
Argument 1 is: 2
Argument 2 is: 3

<?php
function foo($args_one, $args_two = null)
{
    echo $args_one."\t";
    if ($args_two != null) {
        echo $args_two."<br>";
    }
    echo "<br>";
}

foo("one");
foo("one", "two");
?>

one    
one    two