R Regex expression with gsub

Question

I am using gsub regex to select last part of expression

Example:

• "Bla-text-01" - I want -> "text-01"
• "Name-xpto-08" - I want -> "xpto-08"
• "text-text-04" - I want -> "text-04"
• "new-blaxpto-morexpto-07" - I want -> "morexpto-07"
• "new-new-new-bla-ready-05" - I want -> "ready-05"

I created this code that works with first 3 cases but now I have a new request to also work with 5 cases.

gsub(x = match$id,
          pattern =  "(.*?-)(.*)",
          replacement = "\\2")

Can you help me?

Answer 1

x <- c("Bla-text-01",
       "Name-xpto-08", 
       "text-text-04", 
       "new-blaxpto-morexpto-07", 
       "new-new-new-bla-ready-05")

sub("^.*-([^-]*-[^-]*)$", "\\1", x)
## [1] "text-01"     "xpto-08"     "text-04"     "morexpto-07" "ready-05"

Answer 2

Try this regular expression:

sub(".*-(.*-.*)$", "\\1", x)
## [1] "text-01"     "xpto-08"     "text-04"     "morexpto-07" "ready-05"   

Other approaches would be:

# 2. use basename/dirname
xx <- gsub("-", "/", x)
paste(basename(dirname(xx)), basename(xx), sep = "-")
## [1] "text-01"     "xpto-08"     "text-04"     "morexpto-07" "ready-05"   

# 3. use scan
f <- function(x) {
  scan(text = x, what = "", sep = "-", quiet = TRUE) |>  
    tail(2) |>
    paste(collapse = "-")
}
sapply(x, f)
##              Bla-text-01             Name-xpto-08             text-text-04 
##                "text-01"                "xpto-08"                "text-04" 
##  new-blaxpto-morexpto-07 new-new-new-bla-ready-05 
##            "morexpto-07"               "ready-05" 

Note

Input in reproducible form:

x <- c("Bla-text-01", "Name-xpto-08", "text-text-04", "new-blaxpto-morexpto-07", 
"new-new-new-bla-ready-05")