How to remove specific special characters in R

r regex character gsub
wen picture wen · Feb 8, 2014 · Viewed 61k times · Source

I have some sentences like this one.

c = "In Acid-base reaction (page[4]), why does it create water and not H+?"

I want to remove all special characters except for '?&+-/

I know that if I want to remove all special characters, I can simply use

gsub("[[:punct:]]", "", c)
"In Acidbase reaction page4 why does it create water and not H"

However, some special characters such as + - ? are also removed, which I intend to keep.

I tried to create a string of special characters that I can use in some code like this

gsub("[special_string]", "", c)

The best I can do is to come up with this 

cat("!\"#$%()*,.:;<=>@[\\]^_`{|}~.")

However, the following code just won't work

gsub("[cat("!\"#$%()*,.:;<=>@[\\]^_`{|}~.")]", "", c)

What should I do to remove special characters, except for a few that I want to keep?

Thanks

Answer

BrodieG picture BrodieG · Feb 8, 2014 
gsub("[^[:alnum:][:blank:]+?&/\\-]", "", c)
# [1] "In Acid-base reaction page4 why does it create water and not H+?"

Related questions

Removing leading zeros from alphanumeric characters in R

I have a character vector d with alphanumeric characters d <- c("012309 template", "separate 00340", "00045", "890 098", "3405 garage", "matter00908") d [1] "012309 template" "separate 00340" "00045" "890 098" "3405 garage" "matter00908" How can I remove the leading zeros from all the numbers in R? as.numeric will remove all …

Read More
Remove all special characters from a string in R?

How to remove all special characters from string in R and replace them with spaces ? Some special characters to remove are : ~!@#$%^&*(){}_+:"<>?,./;'[]-= I've tried regex with [:punct:] pattern but it removes only punctuation marks. Question 2 : And …

Read More
Replace specific characters within strings

I would like to remove specific characters from strings within a vector, similar to the Find and Replace feature in Excel. Here are the data I start with: group <- data.frame(c("12357e", "12575e", "197e18", "e18947") I start …

Read More