Converting a 10 digit phone number to US format using Regex in Python

Text preprocessing is one of the most important tasks in Natural Language Processing. You may want to extract number from a string. Writing a manual script for such processing task requires a lot of effort and at most times it is prone to errors. Keeping in view the importance of these preprocessing tasks, the concept of Regular Expression have been developed in different programming languages in order to ease these text processing tasks.

To implement Regular Expression, the python re package can be used and to be used it can be easily imported like any other inbuilt python module.

Steps for converting a 10-digit phone number to its corresponding US number format:

• Import the python re package.
• Write a function that takes the phone number to be formatted as argument and processes it. 
• Now simply call the function and pass the value.
   

Example:

import re 

def convert_phone_number(phone):

  # actual pattern which only change this line
  num = re.sub(r'(?<!\S)(\d{3})-', r'(\1) ', phone) 
  return num

# Driver code 
print(convert_phone_number("Call geek 321-963-0612"))

Output:

Call geek (321) 963-0612