regex - Match filename with or without extension

Question

Need a regex pattern to match all of the following:

hello
hello.
hello.cc

I tried \b\w+\.?\w+?\b, but this doesn't match "hello." (the second string mentioned above).

Answer 1

This is about as simple as I can get it:

\b\w+\.?\w*

See demo

Answer 2

The problem is that you enforce the word boundary \b after the dot, which doesn't match and the fact that you require at least one character after with \w+? (lazy matching!). Try this instead:

\b\w+\.?(\w+\b)?

https://regex101.com/r/lX1aE0/1

For more explanations about word boundaries, check this link
http://www.regular-expressions.info/wordboundaries.html