How to apply strsplit to a dataframe in R?

Question

I have a very similar question to this one , but I have a more complicated situation.

Here is my sample code:

test = data.frame(x = c(1:4), 
                 y = c("/abc/werts/h1-1234", "/abc/fghye/seths/h2-234",
                           "/abc/gvawrttd/hyeadar/h3-9868", "/abc/qqras/x1-7653"))
test$y = as.character(test$y)

And I want an output like this:

1 h1-1234
2 h2-234
3 h3-9868
4 x1-7653

I tried:

test$y = tail(unlist(strsplit(test$y, "/")), 1)

However, the result of above codes returned:

1 h1-1234
2 h1-1234
3 h1-1234
4 h1-1234

So my question is, how should modified my code so that I can get my desired output?

Thanks in advance!

Answer 1

Here is the line you are looking for:

test$y = sapply(strsplit(test$y, "/"), tail, 1)

It applies tail to each element in the list returned by strsplit .

Answer 2

Here is an option using sub to match zero or more characters ( .* ) followed by / ( \\\\/ ) followed by zero or more characters that are not a / captured as a group ( ([^/]*) ) until the end ( $ ) of the string, and replace with the backreference ( \\\\1 ) of the capture group

test$y <- sub(".*\\/([^/]*)$", "\\1", test$y)
test$y
#[1] "h1-1234" "h2-234"  "h3-9868" "x1-7653"