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Python Regular Expressions in Python Introduction to Regular Expressions Name Groups

Alex Rodriguez
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Alex Rodriguez
Front End Web Development Techdegree Student 20,810 Points
Posted by Alex Rodriguez
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Alex Rodriguez
Front End Web Development Techdegree Student 20,810 Points

Can't figure out whats wrong with names.py challenge

Instructions: Create a variable names that is an re.match() against string. The pattern should provide two groups, one for a last name match and one for a first name match. The name parts are separated by a comma and a space.

Error: Didn't get the right content in the groups. Last name was "Perotto,", first name was " Pier Giorgio".

My Code:

import re

string = 'Perotto, Pier Giorgio'

names = re.match(r''' (?P<last>[\w]+,) (?P<first>[\s\w]+) ''', string, re.X)

I am no sure what I am doing wrong here, I tried this in workspace and it returned the right answer.

names.py 
import re

string = 'Perotto, Pier Giorgio'

names = re.match(r'''
    (?P<last>[\w]+,)
    (?P<first>[\s\w]+)
''', string, re.X)

2 Answers

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points

You are very close. The separating comma should be outside the group, and you needed to catch the SPACE between the names:

names = re.match(r'''
    (?P<last>[\w]+),\s  # <-- moved comma and added "\s"
    (?P<first>[\s\w]+)
''', string, re.X)
Sahar Nasiri
Sahar Nasiri
7,454 Points
Sahar Nasiri
Sahar Nasiri
7,454 Points

Why do you add the second \s? What's the difference between these \s es?

Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points

The re.X (verbose) flag allows you to write the pattern over several lines but it also then ignores regular spaces. The \s is a placeholder for the SPACE that follows the comma. In other Treehouse challenges, the data is separated by TABs so the \t placeholder will be needed.

Sahar Nasiri
Sahar Nasiri
7,454 Points
Sahar Nasiri
Sahar Nasiri
7,454 Points

Thank you for your answer, But I meant the \s in (?P<first>[\s\w]+). You wrote a \s after "," and then you wrote another one (?P<first>[\s\w]+).

[MOD: fixed format by adding &lt; instead of < and &gt; instead of > -cf]

Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points

The \s in the pattern for "first" was in your original post. I merely copied it. The \s could be replaced by a typed space " ".

I should correct my use of \s. It matches WHITESPACE including space, tab, newline, carriage return, form feed, vertical tab. if you explicitly want a SPACE use the typed " " or enclose it in brackets: [ ]