R中具有多个捕获组的正则表达式组捕获 [英] Regex group capture in R with multiple capture-groups

问题描述

在R中，是否可以从正则表达式匹配中提取组捕获？据我所知， grep ， grepl ， regexpr ， gregexpr ， sub 或 gsub 返回

In R, is it possible to extract group capture from a regular expression match? As far as I can tell, none of grep, grepl, regexpr, gregexpr, sub, or gsub return the group captures.

我需要从经过编码的字符串中提取键值对：

I need to extract key-value pairs from strings that are encoded thus:

\((.*?) :: (0\.[0-9]+)\)

我总是可以做多个完全匹配的抓取，或者做一些外部（非R）处理，但是我希望我可以在R中做所有事情。是否有一个功能或提供此类功能的软件包？

I can always just do multiple full-match greps, or do some outside (non-R) processing, but I was hoping I can do it all within R. Is there's a function or a package that provides such a function to do this?

推荐答案

str_match（），来自 stringr 软件包将执行此操作。它返回一个字符矩阵，在比赛中，每个组都有一列（整个比赛中有一列）：

str_match(), from the stringr package, will do this. It returns a character matrix with one column for each group in the match (and one for the whole match):

> s = c("(sometext :: 0.1231313213)", "(moretext :: 0.111222)")
> str_match(s, "\\((.*?) :: (0\\.[0-9]+)\\)")
     [,1]                         [,2]       [,3]          
[1,] "(sometext :: 0.1231313213)" "sometext" "0.1231313213"
[2,] "(moretext :: 0.111222)"     "moretext" "0.111222"    

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