Regex Sub Phone Number Format Multiple Times On Same String

I'm trying to use reg expressions to modify the format of phone numbers in a list. Here is a sample list: ['(123)456-7890 (321)-654-0987', '(111) 111-1111', '222-222-2222', '(333)3

Solution 1:

Here's a more simple solution that works for all of those cases, though is a little naïve (and doesn't care about matching brackets).

\(?(\d{3})\)?[ -.]?(\d{3})[ -.]?(\d{4})

Replace with:

(\1)\2-\3

Try it online

Explanation:

Works by first checking for 3 digits, and optionally surrounding brackets on either side, with \(?(\d{3})\)?. Notice that the 3 digits are in a capturing group.

Next, it checks for an optional separator character, and then another 3 digits, also stored in a capturing group: [ -.]?(\d{3}).

And lastly, it does the previous step again - but with 4 digits instead of 3: [ -.]?(\d{4})

Python:

To use it in Python, you should just be able to iterate over each element in the list and do:

p.sub('(\\1)\\2-\\3', myString) # Note the double backslashes, or...
p.sub(r'(\1)\2-\3', myString)   # Raw strings work too

Example Python code

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EDIT

This solution is a bit more complex, and ensures that if there is a close bracket, there must be a start bracket.

(\()?((?(1)\d{3}(?=\))|\d{3}(?!\))))\)?[ -.]?(\d{3})[ -.]?(\d{4})

Replace with:

(\2)\3-\4

Try it online