PHP ereg 与 preg

Question

我注意到在 PHP 正则表达式库中可以在 ereg 和 preg 之间进行选择。有什么区别？一个比另一个快吗？如果是，为什么不弃用较慢的那个？

是否存在使用一种优于另一种的情况？

Answer 1

访问 php.net/ereg 显示如下:

Warning

This function has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 6.0.0. Relying on this feature is highly discouraged.

再往下翻一点，我们读到:

Note: preg_match(), which uses a Perl-compatible regular expression syntax, is often a faster alternative to ereg().

注意我强调的重点。