Regex for matching whole words that contain dots

Question

In the following sentence:

I woke up in 5 p.m. today

I want to match the 5 p.m.. This pattern works:

5 p\\         


        

Answer 1

You can use positive lookahead and lookbehind, which is a zero-width match, to do it. A regex like (?<=^|\s)5 p\.m\.(?=\s|$) means "Start of the string or a space character, followed by '5 p.m.' followed by anything which is a space character or end of string."

Answer 2

Well, for that specific example, a simple one would be:

\b5 p\.m\.\B

But I doubt that would work very well in more complex source texts.

This article on word boundaries may be of help.