在 R 中使用 gsub 替换以模式开头的整个单词

Question

我遇到了一个应该很容易解决的问题。我想替换以模式开头的字符串中的整个单词。

> test <- "i really wasn aware and i wasnt aware at all. but i wasn't aware. just wasn't."

    ## this is what i want
    > output
[1] "i really wasn't aware and i wasn't aware at all. but i wasn't aware. just wasn't."

到目前为止我得到的最好的是这个

# this is what get, but it's not correct
> gsub("\<wasn*.\>", "wasn't", test)
[1] "i really wasn't aware and i wasn't aware at all. but i wasn't't aware. Just wasn't't."

我真的运行没主意了。我也会很高兴

 # second desired output without the . at the end
    > output
    [1] "i really wasn't aware and i wasn't aware at all. but i wasn't aware. just wasn't"

编辑：看来我的问题有点太具体了。所以，我正在添加其他测试用例。基本上，我不知道 "wasn" 后面会有什么字符，我想将所有字符都转换为 wasn't

> test <- "i really wasn aware and i wasnt aware at all. but i wasn't aware. just wasn't. this wasn45'e meant to be. it wasn@'re simple"
> test
[1] "i really wasn aware and i wasnt aware at all. but i wasn't aware. just wasn't. this wasn45'e meant to be. it wasn@'re simple"

#desired output
> output
 [1] "i really wasn't aware and i wasn't aware at all. but i wasn't aware. just wasn't. this wasn't meant to be. it wasn't simple"

Answer 1

您可以使用 perl 提供的负面展望.. pattern=wasn(?!')t*

gsub("wasn(?!')t*","wasn't",test,perl=T)
[1] "i really wasn't aware and i wasn't aware at all. but i wasn't aware. just wasn't."

或者你可以这样做：

gsub("wasn'*t*","wasn't",test)
[1] "i really wasn't aware and i wasn't aware at all. but i wasn't aware. just wasn't."

对于第二个期望的输出：

gsub("wasn'*t*[.]?","wasn't",test)
[1] "i really wasn't aware and i wasn't aware at all. but i wasn't aware. just wasn't"

编辑后：

gsub("wasn[^. ]*","wasn't",test)
[1] "i really wasn't aware and i wasn't aware at all. but i wasn't aware. just wasn't. this wasn't meant to be. it wasn't simple"

Answer 2

我建议这样的解决方案：

test <- c("i really wasn aware and i wasnt aware at all. but i wasn't aware. just wasn't. this wasn45'e meant to be. it wasn@'re simple", "Wasn&^$tt that nice?", "You say wasnmmmt?", "No, he wasn&#t#@$.", "She wasn%#@t##, I know.")
 gsub("\b(wasn)\S*\b(?:\S*(\p{P})\B)?", "\1't\2", test, ignore.case=TRUE, perl=TRUE)
[1] "i really wasn't aware and i wasn't aware at all. but i wasn't aware. just wasn't. this wasn't meant to be. it wasn't simple"
[2] "Wasn't that nice?"                                                                                                          
[3] "You say wasn't?"                                                                                                            
[4] "No, he wasn't."                                                                                                             
[5] "She wasn't, I know."

看到 online R demo。

此解决方案解决了 wasn* 出现在字符串开头或被大写但不替换尾随标点符号的情况。

图案详情

\b - 单词边界
(wasn) - 捕获第 1 组（稍后在替换模式中用 \1 引用）：一个 wasn 子字符串（由于 ignore.case=TRUE 不区分大小写）
\S*\b - 除空格外的任何 0+ 个字符后跟单词边界
(?:\S*(\p{P})\B)? - 可选的非捕获组，匹配 1 次或 0 次出现
- \S* - 0+ 个非空白字符
- (\p{P}) - 捕获第 2 组（稍后在替换模式中用 \2 引用）：任意 1 个标点符号（不是符号！\p{P} 不等于 [:punct:]!) 符号后面没有...
- \B - 字母、数字或 _（它是非单词边界模式）。

对于更乱的字符串（如 She wasn%#@t##,$#^ I know.），当标点符号可以在其他标点符号内时，您可以使用自定义括号表达式限制要停止的标点符号并添加 \S* 最后：

gsub("\b(wasn)\S*\b(?:\S*([?!.,:;])\S*)?", "\1't\2", test, ignore.case=TRUE, perl=TRUE)

参见regex demo。

Answer 3

为什么不保持简单，将任何以 wasn 开头的单词替换为 wasn't？

test2 <- paste0(
  "i really wasn aware and i wasnt aware at all. but i wasn't aware. just",
  "wasn't. this wasn45'e meant to be. it wasn@'re simple"
)
gsub("wasn[^ ]*", "wasn't", test2)
[1] "i really wasn't aware and i wasn't aware at all. but i wasn't aware. just wasn't this wasn't meant to be. it wasn't simple"

如果还处理大写字母，那么您可以将 ignore.case = TRUE 添加到 gsub()。

在 R 中使用 gsub 替换以模式开头的整个单词

Replace the whole word that starts with a pattern using gsub in R

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replace

r

gsub