PHP running efficiency summary (prompt program speed)_PHP tutorial

1. When passing an array in a function,
using return is more efficient than using global
For example,

function userloginfo($usertemp){
$detail=explode("|",$usertemp );
return $detail;
}
$login=userloginfo($userdb);
than
function userloginfo($usertemp){
global $detail;
$ detail=explode("|",$usertemp);
}
userloginfo($userdb);

To be efficient
2, (this code is used to get the URL corresponding to the program directory, Recommended)
$urlarray=explode('/',$HTTP_SERVER_VARS['REQUEST_URI']);
$urlcount=count($urlarray);unset($urlarray[$urlcount-1]);
$ofstarurl='http://'.$HTTP_SERVER_VARS['HTTP_HOST'].implode('/',$urlarray);
This code is better than
$pre_urlarray=explode('/',$HTTP_SERVER_VARS ['HTTP_REFERER']);
$pre_url=array_pop($pre_urlarray);
Be efficient
3. When judging in a loop, the use of identity for numerical judgment is more efficient than equal
$a= 2;$b=2;
For example
if($a==$b)$c=$a;
than
if($a===$b)$c=$ a;
Efficient
4. Try to use where in when querying mysql. Use limit less.
limit is used to check the first few records of many records. The speed is very fast, but the query of the last few records will be slow.
Use in. When querying continuous records, it is very fast. The first run of non-continuous records will be a little slower, but it will be faster afterwards!
5, NT server data operation stability is not as stable as unix/linux
6, Before outputting, try to use ob_start(); it can speed up the output. It is suitable for NT or nuli/linux. For unlix servers, if you use ob_start('ob_gzhandler'); the output efficiency will be higher
7. Try to use if when making judgments. ($a==his value) Try to use if(empty($a)) when negating, because this way the program runs faster
8, when using unequal != and <> are equally efficient
9. From personal experience, the efficiency of using $a="11111111111111"; is equivalent to $a='11111111111111';. It is not very different as the book says
10. Using standardized SQL statements will be beneficial to MySQL. Parse
11, use
if($online){
$online1=$online;
setcookie('online1',$online,$cookietime,$ckpath,$ckdomain,$secure);
}

COOKIE will take effect immediately
Use
if($online)
setcookie('online1',$online,$cookietime,$ckpath,$ckdomain,$secure) ;

COOKIE needs to be refreshed again to take effect
12, use
$handle=fopen($filename,wb);
flock($handle,LOCK_SH);
$filedata =fread($handle,filesize($filename));
fclose($handle);
Better than
file($filename);
both in speed and stability
13. Optimization function to truncate strings (can avoid the occurrence of ? characters)
function substrs($content,$length) {
if(strlen($content)>$length){
$num=0 ;
for($i=0;$i<$length-3;$i++) {
if(ord($content[$i])>127)$num++;
}
$num%2==1 ? $content=substr($content,0,$length-4):$content=substr($content,0,$length-3);
$content.=' . ..';
}
return $content;
}

For example, $newarray[1]=substrs($newarray[1],25);
14, in the program Mask case
for ($asc=65;$asc<=90;$asc++)
{ //strtolower() This function will produce garbled characters on some servers!
if (strrpos($regname, chr($asc))!==false)
{
$error="In order to avoid confusion in user names, uppercase letters are prohibited in usernames, please use lowercase letters";
$reg_check=0;
}
}


15, do not use file(); and do not use fget(); (unstable or slow) Take an array function
function openfile($ filename,$method="rb")
{
$handle=@fopen($filename,$method);
@flock($handle,LOCK_SH);
@$filedata=fread( $handle,filesize($filename));
@fclose($handle);
$filedata=str_replace("n","n",$filedata);
$filedb =explode("",$filedata);
//array_pop($filedb);
$count=count($filedb);
if($filedb[$count- 1]==''){unset($filedb[$count-1]);}
return $filedb;
}
//Although this function has more code, it is better in speed and stability The advantage is huge!

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