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Python Regular Expressions in Python Introduction to Regular Expressions Groups

Posted by Sam Dale
Sam Dale
6,136 Points

Can't Solve Blank List Problem

Hi there. No matter what I do I cannot figure out why the following code prints out an empty list. I'm fairly certain that it is all the exact same code as was shown. I'd love it if someone could help me find the obvious mistake that's eluding me. Thanks!

import re

names_file = open("names.txt", encoding = "utf-8")
data = names_file.read()
names_file.close()

print(re.findall(r"""
    ([-\w ]*,\s[-\w ]+)\t  # Last and first names
    ([-\w\d.+]+@[-\w\d.]+)\t  # Email
    (\(?\d{3}\)?-?\s?\d{3}-\d{4})\t  # Phone
    ([\w\s]+,\s[\w\s]+)\t  # Job and company
    (@[\w\d]+)  # Twitter 
    """, data, re.X))

The names.txt looks like:

Love, Kenneth   [email protected]   (555) 555-5555  Teacher, Treehouse  @kennethlove
McFarland, Dave [email protected]  (555) 555-5554  Teacher, Treehouse
Arthur, King    [email protected]   King, Camelot
Österberg, Sven-Erik    [email protected]   Governor, Norrbotten    @sverik
, Tim   [email protected]    Enchanter, Killer Rabbit Cave
Carson, Ryan    [email protected]  (555) 555-5543  CEO, Treehouse  @ryancarson
Doctor, The [email protected]   Time Lord, Gallifrey
Exampleson, Example [email protected]  555-555-5552    Example, Example Co.    @example
Obama, Barack   [email protected] 555 555-5551    President, United States of America @potus44
Chalkley, Andrew    [email protected]    (555) 555-5553  Teacher, Treehouse  @chalkers
Vader, Darth    [email protected]  (555) 555-4444  Sith Lord, Galactic Empire  @darthvader
Fernández de la Vega Sanz, Maria Teresa [email protected] First Deputy Prime Minister, Spanish Govt.
Afrid Mondal
Afrid Mondal
6,255 Points

make the phone optional by adding ? at last and your tab creating the problem maybe. Try this,i think it should help..

import re

names_file = open("names.txt", encoding = "utf-8")
data = names_file.read()
names_file.close()

 print(re.findall(r"""
    ([-\w ]*,\s[-\w ]+)  # Last and first names
    ([-\w\d.+]+@[-\w\d.]+)  # Email
    (\(?\d{3}\)?-?\s?\d{3}-\d{4})? # Phone
   ([\w\s]+,\s[\w\s]+) # Job and company
   (@[\w\d]+)$  # Twitter
    """, data, re.X|re.M))

1 Answer

Chris Freeman
Chris Freeman
68,469 Points
Chris Freeman
Chris Freeman
68,469 Points

I found these errors:

  • the names.txt data wasn't separated by TABs, just spaces. But that might just be a markdown or cut-and-paste issue
  • need to add ? outside of parens for fields that are optional such as email, phone, twitter
  • missing . for company name
  • the re flag for MULTILINE needs to added: re,X | re.M to parse passed the first line
# fixed version
results = re.findall(r"""
    ([-\w ]*,\s[-\w ]+)\t  # Last and first names
    # add ? for option email
    ([-\w\d.+]+@[-\w\d.]+)?\t  # Email
    # add ? for option phone
    (\(?\d{3}\)?-?\s?\d{3}-\d{4})?\t  # Phone
    # add . for company name
    ([\w\s]+,\s[\w\s.]+)\t  # Job and company
    # add ? for option twitter
    (@[\w\d]+)?  # Twitter
    """, data, re.M | re.X)
Chris Freeman
Chris Freeman
68,469 Points
Chris Freeman
Chris Freeman
68,469 Points

Updated answer with complete fixed version.

Sam Dale
Sam Dale
6,136 Points

Thank you. That helped a lot.