经验分享 总结PHP常用函数

PHP常用函数1.产生随机字符串函数

1. function random($length) {  
2. $hash = @#@#;  
3. $chars = @#abcdefghijklmnopqrstuvwxyz0123456789abcdefghijklmnopqrstuvwxyz@#;  
4. $max = strlen($chars) - 1;  
5. mt_srand((double)microtime() * 1000000);  
6. for($i = 0; $i  $length; $i++) {  
7. $hash .= $chars[mt_rand(0, $max)];  
8. }  
9. return $hash;  
10. }  

PHP常用函数2.截取一定长度的字符串

注：该函数对gb2312使用有效

<ol class="dp-xml">
<li class="alt"><span><span>function wordscut($string, $length ,$</span><span class="attribute">sss</span><span>=</span><span class="attribute-value">0</span><span>) {  </span></span></li>
<li>
<span>if(strlen($string) </span><span class="tag">></span><span> $length) {  </span>
</li>
<li class="alt"><span>if($sss){  </span></li>
<li>
<span>$</span><span class="attribute">length</span><span>=$length - 3;  </span>
</li>
<li class="alt">
<span>$</span><span class="attribute">addstr</span><span>=@# ...@#;  </span>
</li>
<li><span>}  </span></li>
<li class="alt">
<span>for($</span><span class="attribute">i</span><span> = </span><span class="attribute-value">0</span><span>; $i </span><span class="tag"><span> $length; $i++) {  </span></span>
</li>
<li>
<span>if(ord($string[$i]) </span><span class="tag">></span><span> 127) {  </span>
</li>
<li class="alt">
<span>$wordscut </span><span class="attribute">.</span><span>= $string[$i].$string[$i + 1];  </span>
</li>
<li><span>$i++;  </span></li>
<li class="alt"><span>} else {  </span></li>
<li>
<span>$wordscut </span><span class="attribute">.</span><span>= $string[$i];  </span>
</li>
<li class="alt"><span>}  </span></li>
<li><span>}  </span></li>
<li class="alt"><span>return $wordscut.$addstr;  </span></li>
<li><span>}  </span></li>
<li class="alt"><span>return $string;  </span></li>
<li><span>}  </span></li>
</ol>

PHP常用函数3.取得客户端ip地址
 

<ol class="dp-xml">
<li class="alt"><span><span>function getip(){  </span></span></li>
<li><span>if (getenv("http_client_ip") <br>&& strcasecmp(getenv("http_client_ip"), "unknown"))  </span></li>
<li class="alt">
<span>$</span><span class="attribute">ip</span><span> = </span><span class="attribute-value">getenv</span><span>("http_client_ip");  </span>
</li>
<li><span>else if (getenv("http_x_forwarded_for") <br>&& strcasecmp(getenv("http_x_forwarded_for"), "unknown"))  </span></li>
<li class="alt">
<span>$</span><span class="attribute">ip</span><span> = </span><span class="attribute-value">getenv</span><span>("http_x_forwarded_for");  </span>
</li>
<li><span>else if (getenv("remote_addr")<br> && strcasecmp(getenv("remote_addr"), "unknown"))  </span></li>
<li class="alt">
<span>$</span><span class="attribute">ip</span><span> = </span><span class="attribute-value">getenv</span><span>("remote_addr");  </span>
</li>
<li><span>else if (isset($_server[@#remote_addr@#])<br> && $_server[@#remote_addr@#] <br>&& strcasecmp($_server[@#remote_addr@#], "unknown"))  </span></li>
<li class="alt">
<span>$</span><span class="attribute">ip</span><span> = $_server[@#remote_addr@#];  </span>
</li>
<li><span>else  </span></li>
<li class="alt">
<span>$</span><span class="attribute">ip</span><span> = </span><span class="attribute-value">"unknown"</span><span>;  </span>
</li>
<li><span>return($ip);  </span></li>
<li class="alt"><span>}  </span></li>
</ol>

PHP常用函数4.创建相应的文件夹
 

<ol class="dp-xml">
<li class="alt"><span><span>function createdir($</span><span class="attribute">dir</span><span>=@#@#)  </span></span></li>
<li><span>{  </span></li>
<li class="alt"><span>if (!is_dir($dir))  </span></li>
<li><span>{  </span></li>
<li class="alt">
<span>$</span><span class="attribute">temp</span><span> = </span><span class="attribute-value">explode</span><span>(@#/@#,$dir);  </span>
</li>
<li>
<span>$</span><span class="attribute">cur_dir</span><span> = @#@#;  </span>
</li>
<li class="alt">
<span>for($</span><span class="attribute">i</span><span>=</span><span class="attribute-value">0</span><span>;$i</span><span class="tag"><span class="tag-name">count</span><span>($temp);$i++)  </span></span>
</li>
<li><span>{  </span></li>
<li class="alt">
<span>$cur_dir </span><span class="attribute">.</span><span>= $temp[$i].@#/@#;  </span>
</li>
<li><span>if (!is_dir($cur_dir))  </span></li>
<li class="alt"><span>{  </span></li>
<li><span>@mkdir($cur_dir,0777);  </span></li>
<li class="alt"><span>}  </span></li>
<li><span>}  </span></li>
</ol>