Replace the dot at the end of a string in R-CodePudding

Here is a string.

"DEL.Xp22.11..ZFX."

I want to replace the .. with a space and a left parenthesis ( and the last . with a right parenthesis ).

"DEL.Xp22.11 (ZFX)"

I tried the following to replace the double dots while I dont know how to replace the last dot.

gsub("..", ' (', "DEL.Xp22.11..ZFX.", fixed = T)

[1] "DEL.Xp22.11 (ZFX."

CodePudding user response：

Try :

x <- "DEL.Xp22.11..ZFX."
x <- gsub("..", ' (', x, fixed = T)
x <- gsub("\\.$", ')', x)

Here I use the regex anchor '$' to signify the end of the word. And '\' to escape the '.' that is a regex special character.

CodePudding user response：

You need to use the following regex-based solution:

sub("\\.{2}([^.] )\\.$", "(\\1)", x)

See the regex demo. Details:

\.{2} - two dots
([^.] ) - Group 1 (\1 refers to this value from the replacement pattern): one or more chars other than a . char
\. - a single dot
$ - end of string.

x <- "DEL.Xp22.11..ZFX."
sub("\\.{2}([^.] )\\.$", "(\\1)", x)
# => [1] "DEL.Xp22.11(ZFX)"