从R中的某个字符截断字符串 [英] truncate string from a certain character in R

问题描述

我在 R 中有一个字符串列表，如下所示:

I have a list of strings in R which looks like:

WDN.TO
WDR.N
WDS.AX
WEC.AX
WEC.N
WED.TO

我想得到所有从字符."开始的字符串的后缀，结果应该是这样的:

I want to get all the postfix of the strings starting from the character ".", the result should look like:

.TO
.N
.AX
.AX
.N
.TO

有人有什么想法吗?

推荐答案

Joshua 的解决方案工作正常.不过，我会使用 sub 而不是 gsub .gsub 用于替换字符串中多次出现的模式 - sub 用于替换一次.模式也可以简化一点:

Joshua's solution works fine. I'd use sub instead of gsub though. gsub is for substituting multiple occurrences of a pattern in a string - sub is for one occurrence. The pattern can be simplified a bit too:

> x <- c("WDN.TO","WDR.N","WDS.AX","WEC.AX","WEC.N","WED.TO")
> sub("^[^.]*", "", x)
[1] ".TO" ".N"  ".AX" ".AX" ".N"  ".TO"

...但是如果字符串和问题中一样规则，那么简单地去除前 3 个字符就足够了:

...But if the strings are as regular as in the question, then simply stripping the first 3 characters should be enough:

> x <- c("WDN.TO","WDR.N","WDS.AX","WEC.AX","WEC.N","WED.TO")
> substring(x, 4)
[1] ".TO" ".N"  ".AX" ".AX" ".N"  ".TO"

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