XC. Regular Expression Functions (POSIX Extended)

介绍

注: PHP also supports regular expressions using a Perl-compatible syntax using the PCRE functions. Those functions support non-greedy matching, assertions, conditional subpatterns, and a number of other features not supported by the POSIX-extended regular expression syntax.

警告

These regular expression functions are not binary-safe. The PCRE functions are.

Regular expressions are used for complex string manipulation in PHP. The functions that support regular expressions are:

These functions all take a regular expression string as their first argument. PHP uses the POSIX extended regular expressions as defined by POSIX 1003.2. For a full description of POSIX regular expressions see the regex man pages included in the regex directory in the PHP distribution. It's in manpage format, so you'll want to do something along the lines of man /usr/local/src/regex/regex.7 in order to read it.

需求

无需外部库文件就可以加入本扩展模块的支持。

安装

To enable regexp support configure PHP --with-regex[=TYPE]. TYPE can be one of system, apache, php. The default is to use php.

注: Do not change the TYPE unless you know what you are doing.

PHP 的 Windows 版本已经内置该扩展模块的支持。您无需加载任何附加的扩展库即可使用这些函数。

运行时配置

该扩展模块未定义任何设置指令。

资源类型

该扩展模块未定义任何资源类型。

预定义常量

该扩展模块未定义任何常量。

范例

例子 1. 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]. */

$string = ereg_replace ("^", "<br />", $string); 
/* Put a <br /> tag at the beginning of $string. */
 
$string = ereg_replace ("$", "<br />", $string); 
/* Put a <br /> tag at the end of $string. */

$string = ereg_replace ("\n", "", $string);
/* Get rid of any newline
   characters in $string. */

相关参考

For regular expressions in Perl-compatible syntax have a look at the PCRE functions. The simpler shell style wildcard pattern matching is provided by fnmatch().

目录
ereg_replace -- Replace regular expression
ereg -- Regular expression match
eregi_replace -- replace regular expression case insensitive
eregi -- case insensitive regular expression match
split -- split string into array by regular expression
spliti --  Split string into array by regular expression case insensitive
sql_regcase --  Make regular expression for case insensitive match