正則表達式常用函數

<?php 
//preg_match("正則表達式","字符串")用于在字符串中查找匹配項 
$email = "987044391@qq.com"; 
if (preg_match("/^([a-zA-Z0-9])+([.a-zA-Z0-9_-])*@([.a-zA-Z0-9_-])+([.a-zA-Z0-9_-]+)+([.a-zA-Z0-9_-])$/",$email)){ echo '匹配成功
'; 
}else { echo '匹配失敗
'; 
} 
//preg_quote("字符串") 在每個有正則表達式語法前面加入一個轉義字符即\ $str = "php點點通是一個學習php的網站，(⊙o⊙)…"; 
echo preg_quote($str); 
echo "
"; //preg_split("正則","字符串")分割字符串 
$php = "+php++點點通++++是好網站"; 
$field = preg_split("/\+{1,}/",$php); 
foreach($field as $f){ 
echo $f." "; 
} 
echo "
"; 
//preg_grep("正則","字符串") 與數組匹配后返回新數組 
$phpddt = array("php點點通","php100","呵呵","hahaha","phpchina"); 
$item = preg_grep("/^php/",$phpddt); 
print_r($item); echo "
"; 
//preg_replace("正則","替換內容","原字符串")  很重要，很常用 
$a = "歡迎光臨http://www.jb51.net/"; //給http開頭的加上超鏈接 
echo preg_replace("/http:\/\/(.*)\//","\${0}","$a"); 
?> 

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