经验分享总结PHP常用函数_PHP教程

PHP常用函数1.产生随机字符串函数

1. function random($length) {
2. $hash = @#@#;
3. $chars = @#abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz@#;
4. $max = strlen($chars) - 1;
5. mt_srand((double)microtime() * 1000000);
6. for($i = 0; $i < $length; $i++) {
7. $hash .= $chars[mt_rand(0, $max)];
8. }
9. return $hash;
10. }

PHP常用函数2.截取一定长度的字符串

注：该函数对gb2312使用有效

function wordscut($string, $length ,$sss=0) {  
if(strlen($string) > $length) {  
if($sss){  
$length=$length - 3;  
$addstr=@# ...@#;  
}  
for($i = 0; $i < $length; $i++) {  
if(ord($string[$i]) > 127) {  
$wordscut .= $string[$i].$string[$i + 1];  
$i++;  
} else {  
$wordscut .= $string[$i];  
}  
}  
return $wordscut.$addstr;  
}  
return $string;  
}  

PHP常用函数3.取得客户端ip地址

function getip(){  
if (getenv("http_client_ip") 
&& strcasecmp(getenv("http_client_ip"), "unknown"))  
$ip = getenv("http_client_ip");  
else if (getenv("http_x_forwarded_for") 
&& strcasecmp(getenv("http_x_forwarded_for"), "unknown"))  
$ip = getenv("http_x_forwarded_for");  
else if (getenv("remote_addr")
 && strcasecmp(getenv("remote_addr"), "unknown"))  
$ip = getenv("remote_addr");  
else if (isset($_server[@#remote_addr@#])
 && $_server[@#remote_addr@#] 
&& strcasecmp($_server[@#remote_addr@#], "unknown"))  
$ip = $_server[@#remote_addr@#];  
else  
$ip = "unknown";  
return($ip);  
}  

PHP常用函数4.创建相应的文件夹

function createdir($dir=@#@#)  
{  
if (!is_dir($dir))  
{  
$temp = explode(@#/@#,$dir);  
$cur_dir = @#@#;  
for($i=0;$i<count($temp);$i++)  
{  
$cur_dir .= $temp[$i].@#/@#;  
if (!is_dir($cur_dir))  
{  
@mkdir($cur_dir,0777);  
}  
}  

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