A brief summary of PHP optimization and high efficiency speed raising

Problem | optimization In a function, it is more efficient to use return than to use global when passing an array, 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
　　
Second, (this code is used to get the program directory corresponding to the URL, recommended use)
　　
$urlarray =explode ('/', $HTTP _server_vars[' Request_uri '));
$urlcount =count ($urlarray); unset ($urlarray [$urlcount-1]);
$ofstarurl = ' http://'. $HTTP _server_vars[' http_host '].implode ('/', $urlarray);
　　
This piece of code is better than
　　
$pre _urlarray=explode ('/', $HTTP _server_vars[' http_referer '));
$pre _url=array_pop ($pre _urlarray);
　　
To be efficient
　　
Third, in the cycle of judgment, the value of the use of identity is equal to high efficiency
$a =2; $b = 2;
Like what
　　
if ($a = = $b) $c = $a;
　　
Than
if ($a = = = $b) $c = $a;
　　
Efficient
　　
Four, MySQL query when possible to use where in less use limit
　　
Limit check more than a few records, the speed is very fast, but the most of the query will be slow
　　
Use in. On query continuity record, very fast, discontinuous records first run will be slightly slower, but later will be faster!
　　
NT Server data operation stability less than unix/linux
　　
Vi. use Ob_start () as far as possible before the output is used; Can speed up output speed, suitable for NT or Nuli/linux, Unlix Class Server if Use Ob_start (' Ob_gzhandler '), output efficiency will be higher
　　
Seven, when the judgement try to use if ($a = = his value) to use if (empty ($a), as far as possible, because the program runs faster.
　　
Viii.!= and <> efficiency are equal when using unequal
　　
Nine, personal experience to use $a = "11111111111111"; The efficiency and $a = ' 11111111111111 '; Quite. Not as much as the book says.
　　
Ten, the use of standardized SQL statements, will be conducive to the analysis of MySQL
　　
Xi. Use of
　　
if ($online) {
$online 1= $online;
Setcookie (' Online1 ', $online, $cookietime, $ckpath, $ckdomain, $secure);
}
　　
The cookie will take effect immediately.
Use
　　
if ($online)
Setcookie (' Online1 ', $online, $cookietime, $ckpath, $ckdomain, $secure);
　　
Cookies need to be refreshed again to take effect
　　
12. Use
　　
$handle =fopen ($filename, WB);
Flock ($handle, lock_sh);
$filedata =fread ($handle, FileSize ($filename));
Fclose ($handle);
　　
Than
　　
File ($filename);
　　
Be good at speed and stability.
　　
13, truncated string optimization function (to avoid the occurrence of the character)
　　
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, the program screen case
　　
For ($asc =65 $asc <=90; $ASC + +)
{//strtolower () This function will generate garbled characters on some servers!
if (Strrpos ($regname, Chr ($ASC))!==false)
{
$error = "In order to avoid user name confusion, the user name is forbidden to use uppercase letters, please use the lowercase letter";
$reg _check=0;
}
}
　　
(), Do not use file (), and do not use Fget ();(unstable or slow) to fetch 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;
}
　　
This function, although the code is more, but in the speed and stability of a great advantage!