使用正则表达式拆分字符串 [英] split string with regex

问题描述

我希望拆分一个通用形式的字符串，其中方括号表示字符串的部分".例如:

I'm looking to split a string of a generic form, where the square brackets denote the "sections" of the string. Ex:

x <- "[a] + [bc] + 1"

并返回一个如下所示的字符向量:

And return a character vector that looks like:

"[a]"  " + "  "[bc]" " + 1"

最终使用了这个:

x <- "[a] + [bc] + 1"
x <- gsub("\\[",",[",x)
x <- gsub("\\]","],",x)
strsplit(x,",")

推荐答案

我看过 TylerRinker 的代码，怀疑它可能比这更清楚，但这可能是学习不同功能集的方式.(在我注意到它在空格上分割之前，我更喜欢他.)我尝试将其调整为与 strsplit 一起使用，但该函数总是删除分隔符.也许这可以用来制作一个 newstrsplit 在分隔符处拆分但将它们留在里面?可能不需要在第一个或最后一个位置拆分并区分打开和关闭分隔符.

I've seen TylerRinker's code and suspect it may be more clear than this but this may serve as way to learn a different set of functions. (I liked his better before I noticed that it split on spaces.) I tried adapting this to work with strsplit but that function always removes the separators. Maybe this could be adapted to make a newstrsplit that splits at the separators but leaves them in? Probably need to not split at first or last position and distinguish between opening and closing separators.

scan(text=   # use scan to separate after insertion of commas
            gsub("\\]", "],",   # put commas in after "]"'s
            gsub(".\\[", ",[",  x)) ,  # add commas before "[" unless at first position
        what="", sep=",")    # tell scan this character argument and separators are ","
#Read 4 items
#[1] "[a]"  " +"   "[bc]" " + 1"

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