str_replace (package stringr) 不能替换 r 中的括号? [英] str_replace (package stringr) cannot replace brackets in r?

问题描述

我有一个字符串，比如说

I have a string, say

 fruit <- "()goodapple"

我想删除字符串中的括号.我决定使用 stringr 包，因为它通常可以处理此类问题.我使用:

I want to remove the brackets in the string. I decide to use stringr package because it usually can handle this kind of issues. I use :

str_replace(fruit,"()","")

但是什么都没有替换，下面替换了:

But nothing is replaced, and the following is replaced:

[1] "()good"

如果我只想更换右半括号，它可以工作:

If I only want to replace the right half bracket, it works:

str_replace(fruit,")","") 
[1] "(good"

然而，左半括号不起作用:

However, the left half bracket does not work:

str_replace(fruit,"(","")

并显示以下错误:

Error in sub("(", "", "()good", fixed = FALSE, ignore.case = FALSE, perl = FALSE) : 
 invalid regular expression '(', reason 'Missing ')''

有人知道为什么会发生这种情况吗?那么如何删除字符串中的()"呢?

Anyone has ideas why this happens? How can I remove the "()" in the string, then?

推荐答案

转义括号可以...

str_replace(fruit,"\\(\\)","")
# [1] "goodapple"

<小时>

您可能还想考虑探索 "stringi" 包，与"stringr"有类似的做法，但功能更灵活.例如，有 stri_replace_all_fixed，它在这里很有用，因为您的搜索字符串是固定模式，而不是正则表达式模式:

---

You may also want to consider exploring the "stringi" package, which has a similar approach to "stringr" but has more flexible functions. For instance, there is stri_replace_all_fixed, which would be useful here since your search string is a fixed pattern, not a regex pattern:

library(stringi)
stri_replace_all_fixed(fruit, "()", "")
# [1] "goodapple"

<小时>

当然，基本的 gsub 也能很好地处理这个:

---

Of course, basic gsub handles this just fine too:

gsub("()", "", fruit, fixed=TRUE)
# [1] "goodapple"

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