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Python Regular Expressions in Python Introduction to Regular Expressions Negation

Iskander Ismagilov
Iskander Ismagilov
13,298 Points
Posted by Iskander Ismagilov
Iskander Ismagilov
13,298 Points

Do not show email with .gov

How should pattern be chaged to do not show emails with .gov at the end from name.txt file?

print(findall(r"\b@[-\w\d.]*[^gov\t]+\b", data, I))

1 Answer

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

You can use a negative lookbehind assertion of the format (?<!...) where ... is the pattern.

First isolate the pattern to match the TopLevelDomain. A "dot" needs to be outside the character class to mark the transition. This will match all email addresses:

print(re.findall(r"@[-\w\d.]+\.[\w\d]+\b", data, re.I))

Now add the negative lookbehind to say "at this point in the pattern the previous characters can not be "gov":

print(re.findall(r"@[-\w\d.]+\.[\w\d]+(?<!.gov)\b", data, re.I))

Note the leading \b is redundant because the @ is already a word boundary.