Some frequently used php functions_PHP tutorial

1. Generate a random string function
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 $hash;
}
2. Intercept a string of a certain length
Note: This function is valid for gb2312
function wordscut($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. Get the client ip address
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. Create the corresponding folder
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. Determine the email address
function checkemail($inaddress)
{
return (ereg("^([a-za-z0-9_-] )+@([a-za-z0-9_-])+(.[a-za-z0-9_-])+",$inaddress));
}
6. Jump Go to
function gotourl($message=@#@#,$url=@#@#,$title=@#@#)
{
$html ="< ;head>";
if(!empty($url))
$html .="";
$html .="";
$html .="

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

"; $html .="" ; $html .=""; $html .="$html .="< ;/tr> ".$title." "; $html . =" ".$message." "; if (!empty($url)) $html .="The system will return in 3 seconds< ;br>If your browser cannot return automatically, please click [here] to enter "; else $html . ="[return]"; $html .="

";
$html .="";
echo $html;
exit;
}
7. Pagination (two functions are used together)
function getpage($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;
}
8.获取新插入数据的id
mysql_insert_id();
?>