经验分享总结PHP常用函数-php手册-php.cn

PHP常用函数1.产生随机字符串函数

function random($length) {
$hash= @#@#;
$chars= @#abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz@#;
$max=strlen($chars) - 1;
mt_srand((double)microtime() * 1000000);
for($i=0; $i$length; $i++) {
$hash.= $chars[mt_rand(0, $max)];
}
return $hash;
}

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; 
 }

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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); 
 }

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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;$icount($temp);$i++)  
 { 
  $cur_dir .= $temp[$i].@#/@#;  
 if (!is_dir($cur_dir)) 
 { 
 @mkdir($cur_dir,0777); 
 } 
 }