// 兩個默認參數(shù)的函數(shù) 
function foo($arg1 = ”, $arg2 = ”) { 
echo “arg1: $arg1\n”; 
echo “arg2: $arg2\n”; 
} 
foo(‘hello','world'); 
/* 輸出:
arg1: hello
arg2: world
*/ 
foo(); 
/* 輸出:
arg1:
arg2:
*/ 

// 是的，形參列表為空 
function foo() { 
// 取得所有的傳入?yún)?shù)的數(shù)組 
$args = func_get_args(); 
foreach ($args as $k => $v) { 
echo “arg”.($k+1).”: $v\n”; 
} 
} 
foo(); 
/* 什么也不會輸出 */ 
foo(‘hello'); 
/* 輸出
arg1: hello
*/ 
foo(‘hello', ‘world', ‘a(chǎn)gain'); 
/* 輸出
arg1: hello
arg2: world
arg3: again
*/
 
 

// 取得所有的后綴為PHP的文件 
$files = glob(‘*.php'); 
print_r($files); 
/* 輸出:
Array
(
[0] => phptest.php
[1] => pi.php
[2] => post_output.php
[3] => test.php
)
*/
 
你還可以查找多種后綴名：
// 取PHP文件和TXT文件 
$files = glob(‘*.{php,txt}', GLOB_BRACE); 
print_r($files); 
/* 輸出:
Array
(
[0] => phptest.php
[1] => pi.php
[2] => post_output.php
[3] => test.php
[4] => log.txt
[5] => test.txt
13.
)
*/
 

$files = glob(‘../images/a*.jpg'); 
print_r($files); 
/* 輸出:
Array
(
[0] => ../images/apple.jpg
[1] => ../images/art.jpg
)
*/

$files = glob(‘../images/a*.jpg'); 
// applies the function to each array element 
$files = array_map(‘realpath',$files); 
print_r($files); 
/* output looks like:
Array
(
[0] => C:\wamp\www\images\apple.jpg
[1] => C:\wamp\www\images\art.jpg
)
*/
 

echo “Initial: “.memory_get_usage().” bytes \n”; 
/* 輸出
Initial: 361400 bytes
*/ 
// 使用內存 
for ($i = 0; $i < 100000; $i++) { 
$array []= md5($i); 
} 
// 刪除一半的內存 
for ($i = 0; $i < 100000; $i++) { 
unset($array[$i]); 
} 
echo “Final: “.memory_get_usage().” bytes \n”; 
/* prints
Final: 885912 bytes
*/ 
echo “Peak: “.memory_get_peak_usage().” bytes \n”; 
/* 輸出峰值
Peak: 13687072 bytes
*/

print_r(getrusage()); 
/* 輸出
Array
(
[ru_oublock] => 0
[ru_inblock] => 0
[ru_msgsnd] => 2
[ru_msgrcv] => 3
[ru_maxrss] => 12692
[ru_ixrss] => 764
[ru_idrss] => 3864
[ru_minflt] => 94
[ru_majflt] => 0
[ru_nsignals] => 1
[ru_nvcsw] => 67
[ru_nivcsw] => 4
[ru_nswap] => 0
[ru_utime.tv_usec] => 0
[ru_utime.tv_sec] => 0
[ru_stime.tv_usec] => 6269
[ru_stime.tv_sec] => 0
)
*/
 

// sleep for 3 seconds (non-busy) 
sleep(3); 
$data = getrusage(); 
echo “User time: “. 
($data['ru_utime.tv_sec'] + 
$data['ru_utime.tv_usec'] / 1000000); 
echo “System time: “. 
($data['ru_stime.tv_sec'] + 
$data['ru_stime.tv_usec'] / 1000000); 
/* 輸出
User time: 0.011552
System time: 0
*/
sleep是不占用系統(tǒng)時間的，我們可以來看下面的一個例子： 
// loop 10 million times (busy) 
for($i=0;$i<10000000;$i++) { 
} 
$data = getrusage(); 
echo “User time: “. 
($data['ru_utime.tv_sec'] + 
$data['ru_utime.tv_usec'] / 1000000); 
echo “System time: “. 
($data['ru_stime.tv_sec'] + 
$data['ru_stime.tv_usec'] / 1000000); 
/* 輸出
User time: 1.424592
System time: 0.004204
*/

$start = microtime(true); 
// keep calling microtime for about 3 seconds 
while(microtime(true) – $start < 3) { 
} 
$data = getrusage(); 
echo “User time: “. 
($data['ru_utime.tv_sec'] + 
$data['ru_utime.tv_usec'] / 1000000); 
echo “System time: “. 
($data['ru_stime.tv_sec'] + 
$data['ru_stime.tv_usec'] / 1000000); 
/* prints
User time: 1.088171
System time: 1.675315
*/

// this is relative to the loaded script's path 
// it may cause problems when running scripts from different directories 
require_once(‘config/database.php'); 
// this is always relative to this file's path 
// no matter where it was included from 
require_once(dirname(__FILE__) . ‘/config/database.php');

// some code 
// … 
my_debug(“some debug message”, __LINE__); 
/* 輸出
Line 4: some debug message
*/ 
// some more code 
// … 
my_debug(“another debug message”, __LINE__); 
/* 輸出
Line 11: another debug message
*/ 
function my_debug($msg, $line) { 
echo “Line $line: $msg\n”;
}
 

// generate unique string 
echo uniqid(); 
/* 輸出
4bd67c947233e
*/ 
// generate another unique string 
echo uniqid(); 
/* 輸出
4bd67c9472340
*/

// 前綴 
echo uniqid(‘foo_'); 
/* 輸出
foo_4bd67d6cd8b8f
*/ 
// 有更多的熵 
echo uniqid(”,true); 
/* 輸出
4bd67d6cd8b926.12135106
*/ 
// 都有 
echo uniqid(‘bar_',true); 
/* 輸出
bar_4bd67da367b650.43684647
*/

// 一個復雜的數(shù)組 
$myvar = array( 
‘hello', 
42, 
array(1,'two'), 
‘a(chǎn)pple' 
); 
// 序列化 
$string = serialize($myvar); 
echo $string; 
/* 輸出
a:4:{i:0;s:5:”hello”;i:1;i:42;i:2;a:2:{i:0;i:1;i:1;s:3:”two”;}i:3;s:5:”apple”;}
*/ 
// 反序例化 
$newvar = unserialize($string); 
print_r($newvar); 
/* 輸出
Array
(
[0] => hello
[1] => 42
[2] => Array
(
[0] => 1
[1] => two
)
[3] => apple
)
*/ 

// a complex array
$myvar = array( 
‘hello', 
42, 
array(1,'two'), 
‘a(chǎn)pple' 

); 
// convert to a string 
$string = json_encode($myvar); 
echo $string; 
/* prints
["hello",42,[1,"two"],”apple”]
*/ 
// you can reproduce the original variable 
$newvar = json_decode($string); 
print_r($newvar); 
/* prints
Array
(
[0] => hello
[1] => 42
[2] => Array
(
[0] => 1
[1] => two
)
[3] => apple
)
*/

$string = 
“Lorem ipsum dolor sit amet, consectetur 
adipiscing elit. Nunc ut elit id mi ultricies 
adipiscing. Nulla facilisi. Praesent pulvinar, 
sapien vel feugiat vestibulum, nulla dui pretium orci, 
non ultricies elit lacus quis ante. Lorem ipsum dolor 
sit amet, consectetur adipiscing elit. Aliquam 
pretium ullamcorper urna quis iaculis. Etiam ac massa 
sed turpis tempor luctus. Curabitur sed nibh eu elit 
mollis congue. Praesent ipsum diam, consectetur vitae 
ornare a, aliquam a nunc. In id magna pellentesque 
tellus posuere adipiscing. Sed non mi metus, at lacinia 
augue. Sed magna nisi, ornare in mollis in, mollis 
sed nunc. Etiam at justo in leo congue mollis. 
Nullam in neque eget metus hendrerit scelerisque 
eu non enim. Ut malesuada lacus eu nulla bibendum 
id euismod urna sodales. “; 
$compressed = gzcompress($string); 
echo “Original size: “. strlen($string).”\n”; 
/* 輸出原始大小
Original size: 800
*/ 
echo “Compressed size: “. strlen($compressed).”\n”; 
/* 輸出壓縮后的大小
Compressed size: 418
*/ 
// 解壓縮 
$original = gzuncompress($compressed);