正则表达式

在PHP中正则表达式用于复杂字符串的处理。所支持的正则表达式如下:

这些函数都使用正则字符串做为第一个参数。PHP使用Posix 1003.2标准所定义的扩展正则字符串。要查考Posix正则表达式的完整描述请看PHP软件包中regex目录下的man页。

Example 2-4. Regular expression examples

ereg("abc",$string); /* Returns true if "abc" is found anywhere in $string. */
ereg("^abc",$string); /* Returns true if "abc" is found at the beginning of $string. */
ereg("abc$",$string); /* Returns true if "abc" is found at the end of $string. */
eregi("(ozilla.[23]|MSIE.3)",$HTTP_USER_AGENT); /* Returns true if client browser is Netscape 2, 3 or MSIE 3. */
ereg("([[:alnum:]]+) ([[:alnum:]]+) ([[:alnum:]]+)",$string,$regs); /* Places three space separated words into $regs[1], $regs[2] and $regs[3]. */
ereg_replace("^","<BR>",$string); /* Put a <BR> tag at the beginning of $string. */
ereg_replace("$","<BR>",$string); /* Put a <BR> tag at the end of $string. */
ereg_replace("\n","",$string); /* Get rid of any carriage return characters in $string. */