5
花了几个小时寻找答案,因为它是在绝望的最后阶段3:15 AM我问这个基本问题(因为我对正则表达式一无所知)。删除所有点,但第一个在charchter字符串
我想替换除连续第一个点外的所有点。这里是我想要的一个例子:
> names.orig <- c("test & best", "test & worse &&&& ? do")
> names <- make.names(names.orig)
> names
[1] "test...best" "test...worse.........do"
>
> # But I want this instead:
> # [1] "test.best" "test.worse.do"
>
> # Desperatley tried:
> gsub("\\.{2, }", "", names)
[1] "testbest" "testworsedo"
> gsub("\\G((?!^).*?|[^\\.]*\\.*?)\\.", "", names)
Error in gsub("\\G((?!^).*?|[^\\.]*\\.*?)\\.", "", names) :
invalid regular expression '\G((?!^).*?|[^\.]*\.*?)\.', reason 'Invalid regexp'
> # etc.
>
> # The only thing that works for me is this
> unlist(lapply(strsplit(names, "\\."), function(x) paste(x[x != ""], collapse=".")))
[1] "test.best" "test.worse.do"
>
> # But, really, what is the right regex in combination with what?
任何提示如何解决与正则表达式赞赏。
其简单可以替换。+来。 – Civa