Go正则表达式中的负向超前 [英] Negative look-ahead in Go regular expressions

问题描述

我正在尝试在Go语言中使用否定的前瞻功能.

I'm trying to use negative look-aheads in Go.

以下正则表达式:BBB(((?!BBB).)*)EEE

http://rubular.com/r/Zw1vopp1MF

但是，在Go中，我得到了:

However, in Go I get:

error parsing regexp: invalid or unsupported Perl syntax: `(?!`

还有其他选择吗?

推荐答案

出于技术原因，不支持负超前查找，特别是因为它与库的O(n)时间保证冲突.有关此内容，请参见 golang-nuts小组讨论，以及野生型正则表达式匹配.

Negative lookahead isn't supported for technical reasons, specifically because it conflicts with the O(n)-time guarantees of the library. See the golang-nuts group discussion about this, as well as the Caveats section in Regular Expression Matching in the Wild.

您可以表达所描述的正则表达式而不会产生负面的提前提示:

You can express the regular expression you've described without negative lookahead:

BBB([^B]|B[^B]|BB[^B])*EEE

下面是一个示例，用于演示:

Here's an example to demonstrate:

package main

import (
    "fmt"
    "regexp"
)

func main() {
    re := regexp.MustCompile(`BBB([^B]|B[^B]|BB[^B])*EEE`)
    fmt.Printf("%#v\n", re.FindAllString("BBB EEE BBB..BBB...EEE", -1))
}

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