Today I learned how I can use the method 'groupdict' from a regex match to get a dictionary with all named groups.

re.Match.groupdict

Python regular expressions support named groups, which are introduced with the flag ?P<name>:

import re

date = re.compile(
    r"""(?x)  # Use ?x for verbose regex
    (?P<year>\d{4})  # year = 4 digits, e.g., 2025
    -
    (?P<month>\d{1,2})  # month = 1 or 2 digits, e.g., 01 or 1
    -
    (?P<day>\d{1,2})  # day = 1 or 2 digits
    """
)

match = date.match("2025-01-22")
print(match.group("year"))  # 2025

If you have named groups, you can then use the method groupdict to get a dictionary with all groups and their matches:

match = date.match("2025-01-22")
print(match.groupdict())  # {'year': '2025', 'month': '01', 'day': '22'}

This is the counterpart to groups that produces a tuple with all groups in the order they appear:

match = date.match("2025-01-22")
print(match.groups())  # ('2025', '01', '22')

While groups shows the values of all groups, regardless of whether they're named or not, groupdict will only show named groups:

date2 = re.compile(r"(\d{4})-(\d{1,2})-(\d{1,2})")
match = date2.match("2025-01-22")
print(match.groups())  # ('2025', '01', '22')
print(match.groupdict())  # {}

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