更新时间:2022-11-14 19:32:50
否定的超前行将不起作用,因为-使用 *?
(懒惰的零或更多)量词-它将在 S
并在前面没有找到 Impl
,因此匹配成功.
A negative lookahead wont work because - with the *?
(lazy zero-or-more) quantifier - it'll check at S
and find no Impl
immediately ahead so the match succeeds.
如果您更改为贪婪的量词(将 *
更改为 *?
),它仍然会失败,因为您将位于字符串的末尾-没有前进".
If you changed to a greedy quantifier (change *
to *?
) it would still fail because you would be at the end of the string - there is no "ahead" to look at.
相反,您想在后面使用负面表情 来检查先前的内容,即
Instead you want to use a negative lookbehind to check the previous content, i.e.
[A-Z][A-Za-z\d]*(?<!Impl)
(您可能不希望 $
结尾,具体取决于使用模式的位置)
(You may or not want $
at the end of that, depending on where the pattern is used)
旁注:此处不直接相关,但有用的是(在Java正则表达式中)后视必须具有有限的宽度-您不能使用 *
或+
量词,而必须使用有限的数字量词,例如 {0,99}
Side note: not directly relevant here, but useful to know is that (in Java regex) a lookbehind must have a limited width - you can't use *
or +
quantifiers, and must instead use limited numerical quantifiers, e.g. {0,99}
但是,除非模式本身很重要(或者您必须在使用正则表达式的环境中工作),否则更简单的选项将是
But unless the pattern itself is important (or you're working in a context where you must use regex), a simpler option would be String.endsWith, like so:
! mystring.endsWith('Impl')