Return a string between two characters '.'

Question

I have column names similar to the following

names(df_woe)

# [1] "A_FLAG" "woe.ABCD.binned" "woe.EFGHIJ.binned"       
 ...

I would like to rename the columns by removing the "woe." and ".binned" sections, so that the following will be returned

names(df_woe)
# [1] "A_FLAG" "ABCD" "EFGHIJ"       
 ...

I have tried substr(names(df_woe), start, stop) but I am unsure how to set variable start/stop arguments.

Answer 1

Another possible and readable regex can be to create groups and return the group after the first and before the second dot, ie

gsub("(.*\\.)(.*)\\..+", "\\2", names(df_woe))
#[1] "A_FLAG" "ABCD"   "EFGH"

Answer 2

nam <- c("A_FLAG", "woe.ABCD.binned", "woe.EFGH.binned")
gsub("woe\\.|\\.binned", "", nam)
[1] "A_FLAG" "ABCD"   "EFGH"  

EDIT: a solution that deals with wierder cases such as woe..binned.binned

gsub("^woe\\.|\\.binned$", "", nam)

Answer 3

Another solution, using stringr package:

 str_replace_all("woe.ABCD.binned", pattern = "woe.|.binned", replacement = "")
 # [1] "ABCD"