Question

我正在尝试在一组字符串上使用gsub，这些字符串可能会略微改变措辞;

I went to the store last night
I went to the park yesterday
I went to starbucks this morning

我需要使用gsub来代替＆＃39;我去了...＆＃39;，但有时它会有一个＆＃39;＆＃39;有时它不会

这样的事情，但以下不能正常工作

gsub('i went to [the|a-z]','REPLACED',string)

REPLACED last night
REPLACED yesterday
REPLACED this morning

Answer 1

尝试：

gsub("I went to (the )?[a-z]", "REPLACED", string)

Answer 2

您可以将stringr包与以下正则表达式一起使用（使用^锚定在字符串的前面）：

library(stringr)
sentences <- c("I went to the store last night",
               "I went to the park yesterday",
               "I went to starbucks this morning")
str_replace(sentences, "^I went to( the)?", "REPLACED")
# [1] "REPLACED store last night"       "REPLACED park yesterday"        
# [3] "REPLACED starbucks this morning"

如果在同一个字符串中有多个要替换的实例，您可能希望省略^并使用str_replace_all()

R gsub多个条件

2 个答案: