CODEWITHSUNDEEP
r
Anika
Anika

Reputation: 27

Replacing a numeric value in parenthesis in R

I have a data frame, lets call is bob. bob has a column called "Rate" where the factor levels are a bunch of numeric values. I want to take the value in parenthesis and replace it with their negative values. For example: (50.00) now replace it with -50.00. There are several values within the column that are in parenthesis but I'm trying to find an efficient way. I have tried group<-(levels(bob$Rate))

" gsub(\\(|\\)", "-", group)   But this changes (50.00) to -50.00- and I tried 

 gsub("\\(", "-", group)  replaces ( with -
 gsub("\\)", "", group) replaces ) with "" but it can only do one or the other not both.

Upvotes: 0

Views: 478

Answers (1)

Roland
Roland

Reputation: 132969

Use a backreference:

gsub("(\\()(\\d+\\.?\\d*)(\\))", 
     "-\\2", 
     c("2.1", "20", "(50)", "(7.1)"), perl = TRUE)
#[1] "2.1"  "20"   "-50"  "-7.1"

Upvotes: 2

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