R gsub a single double quotation mark

问题

I have a field of strings in a data frame all similar to:

"Young Adult – 8-9"" 

where the inner single " is what I want to replace with nothing to get:

"Young Adult - 8-9"

How can I do this? I tried to escape with a double backslash:

gsub("\\"", "", string)

but got this error: Error: unexpected string constant in "gsub("\"", ""

回答1:

You do not need to escape a double quote in a regular expression. Just use "\"" or '"' to match a single double quote.

s = "Young Adult – 8-9\""
s
[1] "Young Adult – 8-9\""
gsub("\"", "", s)
[1] "Young Adult – 8-9"
gsub('"', "", s)
[1] "Young Adult – 8-9"

See this IDEONE demo

NOTE: Since you want to remove some literal text, you do not even need a regex, use fixed=TRUE argument to speed up the operation:

gsub('"', "", s, fixed=TRUE)

来源：https://stackoverflow.com/questions/37282579/r-gsub-a-single-double-quotation-mark