将角色分成几部分 [英] Spliting the character into parts

问题描述

我观察到以下字符:

  l <- "mod, range1 = seq(-m, n, 0.1), range2 = seq(-2, 2, 0.1), range3 = seq(-2, 2, 0.1)"

在R中使用正则表达式我希望将l拆分为以下结构:

Using regular expressions in R I desire to split l in the following structure:

[1] "mod"                      "range1 = seq(-m, n, 0.1)"
[3] "range2 = seq(-2, 2, 0.1)" "range3 = seq(-2, 2, 0.1)"

不幸的是，我还没有找到解决问题的合适方法.任何人都有一个想法如何获得这种选举分裂?

Unfortunetely, I didn't find a proper way to overcome the problem, yet. Anyone has an idea how is it possible to acquire such an elegeant split?

推荐答案

我真的怀疑您可以使用正则表达式来做到这一点.您正在尝试解析您的字符串，因此您需要一个解析器，该解析器通常比正则表达式更强大.我认为它不够通用，但是您可以利用R解析器和alist类.试试:

I really doubt you can do it with regular expression. You are trying to parse your string and so you need a parser, which is generally more powerful than a regex. I don't think it's general enough, but you can take advantage of the R parser and the alist class. Try:

res<-eval(parse(text=paste0("alist(",l,")")))
paste0(names(res),ifelse(names(res)!="","=",""),as.character(res))
#[1] "mod"                    "range1=seq(-m, n, 0.1)" "range2=seq(-2, 2, 0.1)"
#[4] "range3=seq(-2, 2, 0.1)"

请记住，如果有嵌套括号，则regex建议的解决方案将失败.尝试一下并使用以下方法进行挖掘:

Keep in mind that the regex proposed solutions fail if there are nested brackets. Try them and mine with:

l<-"mod, range1 = seq(-m, n, 0.1), range2 = seq(-2, exp(2), 0.1), range3 = seq(-2, 2, 0.1)"

了解我的意思.

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