英文:
R: save a regex match to a new variable while removing the regex match from the existing variable using `str_extract()`
问题
我想将正则表达式匹配保存到新变量，并在同一个函数中从现有变量中移除正则表达式匹配。所以在以下示例中，我想从句子中移除“Speaker. ”并将其保存到`new_variable`，同时也从`sentence`中移除“Speaker. ”。我尝试使用`str_extract()`来实现这一点。我能够匹配所需的单词，但该单词未从`sentence`中移除。（这可能不是`str_extract()`的设计目的，那么`str_extract()`和`str_match()`之间有什么区别？）
library(stringr)
sentence <- "Speaker. I am not sure why this does not work."
for(line in sentence) {
new_variable <- str_extract(line, "^[[:alpha:]]+\. ")
}
我知道可以使用`str_replace()`从句子中删除正则表达式匹配，但如果可能的话，我更愿意使用一个函数来实现这一点。
library(stringr)
sentence <- "Speaker. I am not sure why this does not work."
for(line in sentence) {
new_variable <- str_extract(line, "^[[:alpha:]]+\. ")
sentence <- str_replace(sentence, test, "")
}
英文:
I want to save a regex match to a new variable and remove the regex match from the existing variable using one function.
So in the following example, I want to remove "Speaker. " from sentence and save it to new_variable while also removing "Speaker. " from sentence.
I tried to accomplish this with str_extract(). I am able to match the desired word, but the word is not removed from sentence. (This may not be what str_extract() was designed to do, but then what is the difference between str_extract() and str_match()??)
library(stringr)sentence <- "Speaker. I am not sure why this does not work."for(line in sentence) {new_variable <- str_extract(line, "^[[:alpha:]]+\\. ")}
I know I can use str_replace() to remove the regex match from sentence, but I would prefer to do this with one function if possible.
library(stringr)sentence <- "Speaker. I am not sure why this does not work."for(line in sentence) {new_variable <- str_extract(line, "^[[:alpha:]]+\\. ")sentence <- str_replace(sentence, test, "")}
答案1
得分: 1
你可以使用 tidyr::separate_wider_regex 函数：
library(tidyr)df <- data.frame(sentence = "Speaker. I am not sure why this does not work.")separate_wider_regex(df, sentence, c(new_variable = "^[[:alpha:]]+\\. ", sentence = ".*"))
# A tibble: 1 × 2new_variable sentence<chr> <chr>1 "Speaker. " I am not sure why this does not work.
英文:
You can use tidyr::separate_wider_regex
library(tidyr)df <- data.frame(sentence = "Speaker. I am not sure why this does not work.")separate_wider_regex(df, sentence, c(new_variable = "^[[:alpha:]]+\\. ", sentence = ".*"))
# A tibble: 1 × 2new_variable sentence<chr> <chr>1 "Speaker. " I am not sure why this does not work.
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