一些使用频率比较高的php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;
}

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))
$html .="<Meta http-equiv=@#refresh@# content=\"3;url=@#".$url."@#\">";
$html .="";
$html .="

";
$html .="";
$html .="";
$html .="

";
$html .="";
$html .="$html .="

";
$html .="
".$message."

";
if (!empty($url))
$html .="系统将在3秒后返回
如果您的浏览器不能自动返回,请点击[这里]进入";
else
$html .="[返回]";
$html .="$html .="";
echo $html;
exit;
}

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;
}