如何使用正则表达式用逗号分隔除括号内的字符串外的字符串? [英] How do I split a string by commas except inside parenthesis, using a regular expression?

问题描述

我想用逗号分割一个字符串:

I want to split a string by comma:

"a,s".split ','  # => ['a', 's']

如果子字符串被括号括起来，我不想拆分它:

I don't want to split a sub-string if it is wrapped by parenthesis:

"a,s(d,f),g,h"

应该产生:

['a', 's(d,f)', 'g', 'h']

有什么建议吗?

推荐答案

处理嵌套括号，可以使用:

To deal with nested parenthesis, you can use:

txt = "a,s(d,f(4,5)),g,h"
pattern = Regexp.new('((?:[^,(]+|(\((?>[^()]+|\g<-1>)*\)))+)')
puts txt.scan(pattern).map &:first

图案详情:

(                        # first capturing group
    (?:                  # open a non capturing group
        [^,(]+           # all characters except , and (
      |                  # or
        (                # open the second capturing group
           \(            # (
            (?>          # open an atomic group
                [^()]+   # all characters except parenthesis
              |          # OR
                \g<-1>   # the last capturing group (you can also write \g<2>)
            )*           # close the atomic group
            \)           # )
        )                # close the second capturing group
    )+                   # close the non-capturing group and repeat it
)                        # close the first capturing group

第二个捕获组描述嵌套括号，可以包含不是括号的字符或捕获组本身.这是一个递归模式.

The second capturing group describe the nested parenthesis that can contain characters that are not parenthesis or the capturing group itself. It's a recursive pattern.

在模式内部，可以用他的编号(\g<2>为第二个捕获组)或他的相对位置(\g<-1>; 模式中当前位置左侧的第一个)(如果使用命名捕获组，则使用他的名字)

Inside the pattern, you can refer to a capture group with his number (\g<2> for the second capturing group) or with his relative position (\g<-1> the first on the left from the current position in the pattern) (or with his name if you use named capturing groups)

注意:如果在非捕获组末尾添加|[()]，则可以允许使用单括号.然后 a,b(,c 会给你 ['a', 'b(', 'c']

Notice: You can allow single parenthesis if you add |[()] before the end of the non-capturing group. Then a,b(,c will give you ['a', 'b(', 'c']

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