这是一些使用频率比较高的PHP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;
}

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;
}

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);
}

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

5.判断邮箱地址

function checkEmail($inAddress)
{
return (ereg(”^([a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+(.[a-zA-Z0-9_-])+”,$inAddress));

}

6.跳转

function gotourl($message=”,$url=”,$title=”)
{

$html =””;
if(!empty($url))
$html .=””;
$html .=””;
$html .=”

7.分页（两个函数配合使用）

function getpage($sql,$page_size=20)
{
global $page,$totalpage,$sums; //out param
$page = $_GET["page"];
//$eachpage = $page_size;
$pagesql = strstr($sql,” from “);
$pagesql = “select count(*) as ids “.$pagesql;
$result = mysql_query($pagesql);
if($rs = mysql_fetch_array($result)) $sums = $rs[0];
$totalpage = ceil($sums/$page_size);
if((!$page)||($page<1)) $page=1;
$startpos = ($page-1)*$page_size;
$sql .=” limit $startpos,$page_size “;
return $sql;
}

function showbar($string=”")
{
global $page,$totalpage;
$out=”共”.$totalpage.”页 ”;
$linkNum =4;
$start = ($page-round($linkNum/2))>0 ? ($page-round($linkNum/2)) : “1″;
$end = ($page+round($linkNum/2))<$totalpage ? ($page+round($linkNum/2)) : $totalpage;
$prestart=$start-1;
$nextend=$end+1;
if($page<>1)
$out .= “第一页 ”;
if($start>1)
$out.=”..<< ”;
for($t=$start;$t<=$end;$t++)
{
$out .= ($page==$t) ? “[".$t."] ” : “$t ”;
}
if($end<$totalpage)
$out.=”>>..”;
if($page<>$totalpage)
$out .= “ 最后页”;
return $out;
}

?>