9个必须知道的实用PHP函数和功能

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

 echo "arg1: $arg1n";
 echo "arg2: $arg2n";

}

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

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

// 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).": $vn";
 }

}

foo();
/* prints nothing */

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

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

// get all php files
$files = glob('*.php');

print_r($files);
/* output looks like:
Array
(
    [0] => phptest.php
    [1] => pi.php
    [2] => post_output.php
    [3] => test.php
)
*/

// get all php files AND txt files
$files = glob('*.{php,txt}', GLOB_BRACE);

print_r($files);
/* output looks like:
Array
(
    [0] => phptest.php
    [1] => pi.php
    [2] => post_output.php
    [3] => test.php
    [4] => log.txt
    [5] => test.txt
)
*/