python-regexHow to use named groups with regex in Python?

Named groups are a powerful tool for regex in Python. They allow you to assign names to parts of a regular expression, making it easier to read and maintain. To use named groups, you need to use the syntax (?P<name>pattern), where name is the name of the group and pattern is the regular expression pattern.

For example, the following code uses named groups to match a date string:

import re

date_regex = re.compile(r"(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2})")

date_string = "2020-05-15"

match = date_regex.match(date_string)

print(match.group("year"))  # Output: 2020
print(match.group("month")) # Output: 05
print(match.group("day"))   # Output: 15

Code explanation

• (?P<name>pattern): This is the syntax for creating a named group. name is the name of the group and pattern is the regular expression pattern.
• date_regex = re.compile(r"(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2})"): This line creates a regular expression object with three named groups: year, month, and day.
• match = date_regex.match(date_string): This line uses the regular expression object to match the date string.
• print(match.group("year")): This line prints the value of the year group from the match.

Helpful links

• Python Regular Expression Tutorial
• Python re Module Documentation

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