Python Replace an Undetermined length of Text

Question

I have a string like this:

Hi. My name is _John_. I am _20_ years old.

and I'd like to convert it into this:

Hi. My name is <b>John</b>. I am <b>20</b> years old.

I did something like this but no luck.

import re
text = "Hi. My name is _John_. I am _20_ years old."
pattern = "(.*)(\_)(.*)(\_)(.*)"
re.sub(pattern, r'\1<b>\3</b>\5', text)
'Hi. My name is _John_. I am <b>20</b> years old.'

What is wrong with the pattern? Why is it not seeing the first bold text?

Any help would be appreciated. Thanks.

Answer 1

Change to:

pattern = "_([^_]*)_"
re.sub(pattern, r'<b>\1</b>', text)

Also see this example.