<?php /* 判断字符串是否存在的函数 */ function strexists($haystack, $needle) { return !(strpos($haystack, $needle) === FALSE);//注意这里的"===" } /* Test */ $mystring = 'abc'; $findme = 'a'; $pos = strpos($mystring, $findme); // Note our use of ===. Simply == would not work as expected // because the position of 'a' was the 0th (first) character. // 简单的使用 "==" 号是不会起作用的，需要使用 "==="，因为 a 第一次出现的位置为 0 if ($pos === false) { echo "The string '$findme' was not found in the string '$mystring'"; } else { echo "The string '$findme' was found in the string '$mystring'"; echo " and exists at position $pos"; } // We can search for the character, ignoring anything before the offset // 在搜索字符的时候可以使用参数 offset 来指定偏移量 $newstring　= 'abcdef abcdef'; $pos　= strpos($newstring, 'a', 1); // $pos = 7, not 0 ?>