Remove last occurrence of character

Question

A question came across talkstats.com today in which the poster wanted to remove the last period of a string using regex (not strsplit). I made an attempt to do thi

Answer 1

You need this regex: -

[.](?=[^.]*$)

And replace it with empty string.

So, it should be like: -

gsub("[.](?=[^.]*$)","",N,perl = TRUE)

Explanation: -

[.]         // Match a dot
(?=         // Followed by
    [^.]    // Any character that is not a dot.
     *      // with 0 or more repetition
     $      // Till the end. So, there should not be any dot after the dot we match.
)  

So, as soon as a dot(.) is matched in the look-ahead, the match is failed, because, there is a dot somewhere after the current dot, the pattern is matching.