我試圖洗掉模式之前的所有內容，但是當它有一個“？” 和空格我認為它不起作用。
question <- "How much do you agree or disagree to the following statements? - I am happy"
str_remove(question, "How much do you agree or disagree to the following statements? - ")
[1] "How much do you agree or disagree to the following statements? - I am happy"
如果我這樣做，我會得到這個：
str_remove(question, "How much do you agree or disagree to the following statements?")
[1] "? - I am happy"
最后，我只想得到這個：
[1] "I am happy"
uj5u.com熱心網友回復：
我們可以更改模式以匹配字符 ( .*) 后跟?(元字符 - 所以轉義\\)，后跟一個或多個空格 ( \\s ) 然后 a-和多個空格之一 ( \\s )
library(stringr)
str_remove(question, ".*\\?\\s -\\s ")
[1] "I am happy"
在base R，使用trimws
trimws(question, whitespace = ".*\\?\\s -\\s ")
[1] "I am happy"
uj5u.com熱心網友回復：
它看起來像是?被解釋為一個正則運算式量詞（https://www.rexegg.com/regex-quickstart.html）。
您可以使用fixed=TRUE從字面上解釋模式。
question <- "How much do you agree or disagree to the following statements? - I am happy"
sub(pattern = "How much do you agree or disagree to the following statements? - ",
replacement = "",
x = question,
fixed = TRUE)
[1] "I am happy"
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