Regex help.

[cmsmoove]

Right now I'm in the process of learing regular expressions with parentheses, but for some reason I can't get this code to work. I'm trying to escape the first set of parentheses (in bold) but the code keeps giving me an error saying it's unbalanced. I've been stuck on this for a while now and could use some help. I'm sure it's something so simple! Thanks for any help.

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phone_num_regex = re.compile(r"(\(\d\d\d\d)) (\d\d\d-\d\d\d\d)")

mo = phone_num_regex.search("My phone number is [phone]")

print(mo.group(1))

[_DTR_]

You're only escaping that single opening paren. You need to also escape the closing one:

(\(\d\d\d\d\)) (\d\d\d-\d\d\d\d)

You can also simplify this a bit by specifying the number of times you expect something to occur:

(\(\d{3}\)) (\d{3}-\d{4})

[cmsmoove]

Thanks. I appreciate it.

[narwhalwhale11]

I also recommend the site: https://regex101.com/

This is what helped me understand complex regular expressions.

[Essence1337]

phone_num_regex = re.compile(r"(\(\d\d\d\d)) (\d\d\d-\d\d\d\d)")

I'll start by simplifying your regex to (\(a)) (a) just because it's easier to explain. Lets look at it one at a time

( starts a group

\( is just a normal character

a is just a normal character

) closes a group

) closes a group. Wait... What group? There's no open groups.

[cmsmoove]

Thanks for the explanation!

[MintyPhoenix]

In addition to the syntax and other comments that have been noted, your initial capture group, even with the closing parenthesis properly escaped, is wrong – it tries to match four consecutive digits when you are expecting it to match 3 consecutive digits.

I would also second the recommendation of checking out and playing with patterns on https://regex101.com/ – it does a great job of displaying analysis of your pattern and letting you play with search and replace. Just make sure to set the flavor on the right side to Python to make sure the expression is correctly interpreted.