Filtering phone numbers

Now, you need to write a script for a cell-phone searcher. It should scan a list of phone numbers and return those that meet certain characteristics.

The phone numbers in the list have the structure:

Optional area code: 3 numbers
Prefix: 4 numbers
Line number: 6 numbers
Optional extension: 2 numbers

E.g. 654-8764-439434-01.

You decide to use .findall() and the non-capturing group's negative lookahead (?!) and negative lookbehind (?<!).

The list cellphones, containing three phone numbers, and the re module are loaded in your session. You can use print() to view the data in the IPython Shell.

1
Get all phone numbers that are not preceded by the optional area code.
2
Get all the phone numbers that are not followed by the optional extension.

Exercise

Filtering phone numbers

Instructions 1/2