3  

The fact that

这一事实

^(?![_-])(\w+)[_-](\w+)(?<![_-])$

does not match the second hyphen in "eslint-global-path" is because of the anchor ^ which limits the match to be on the first hyphen only. This regex reads, "Match the beginning of the line, not followed by a hyphen or underscore, then match one or more words characters (including underscores), a hyphen or underscore, and then one or more word characters in a capture group. Lastly, do not match a hyphen or underscore at the end of the line."

第二个字符不匹配“eslint-global-path”是因为锚^这限制了比赛的第一个字符。这个regex将读取“匹配行首，而不是连字符或下划线，然后匹配一个或多个单词字符(包括下划线)、一个连字符或下划线，然后是捕获组中的一个或多个单词字符。”最后，不要在行尾匹配连字符或下划线。

The fact that an underscore (but not a hyphen) is a word (\w) character completely messes up the regex. In general, rather than using \w, you might want to use \p{Alpha} or \p{Alnum} (or POSIX [[:alpha:]] or [[:alnum:]]).

下划线(而不是连字符)是一个单词(\w)，这一事实完全打乱了正则表达式。一般情况下，您可能希望使用\p{Alpha} or \p{Alnum}(或POSIX [: Alpha:])或[[:Alnum:]]。

Try this.

试试这个。

r = /
    (?<=     # begin a positive lookbehind
      [^_-]  # match a character other than an underscore or hyphen
    )        # end positive lookbehind
    (        # begin capture group 1
      (?:    # begin a non-capture group
        -+   # match one or more hyphens
        |    # or
        _+   # match one or more underscores
      )      # end non-capture group
      [^_-]  # match any character other than an underscore or hyphen
    )        # end capture group 1
    /x       # free-spacing regex definition mode

'_cats_have--nine_lives--'.gsub(r) { |s| s[-1].upcase }
  #=> "_catsHaveNineLives--"

This regex is conventionally written as follows.

这个regex按照惯例是这样写的。

r = /(?<=[^_-])((?:-+|_+)[^_-])/

If all the letters are lower case one could alternatively write

如果所有的字母都是小写字母，你可以选择写

'_cats_have--nine_lives--'.split(/(?<=[^_-])(?:_+|-+)(?=[^_-])/).
  map(&:capitalize).join
  #=> "_catsHaveNineLives--"

where

在哪里

'_cats_have--nine_lives--'.split(/(?<=[^_-])(?:_+|-+)(?=[^_-])/)
  #=> ["_cats", "have", "nine", "lives--"]

(?=[^_-]) is a positive lookahead that requires the characters on which the split is made to be followed by a character other than an underscore or hyphen

(? =(^ _ -))是一个积极的超前,需要的字符分割是紧随其后的是一个下划线或连字符以外的字符

0  

you can try the regex

你可以试试regex

^(?=[^-_])(\w+[-_]\w*)+(?=[^-_])\w$

see the demo here.

看到演示。

-1  

Switch _- to -_ so that - is not treated as a range op, as in a-z.

开关_- to -_，这样就不会像在a-z中那样被当作一个范围操作。