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How does functools.total_ordering reduce boilerplate for comparison methods?

Intermediate

Answer

total_ordering takes a class that defines __eq__ and one of __lt__, __le__, __gt__, or __ge__, then fills in the remaining comparison methods automatically. This avoids manually writing all six rich comparison methods for classes that need full ordering support.
from functools import total_ordering

@total_ordering
class Version:
    def __init__(self, num):
        self.num = num
    def __eq__(self, other):
        return self.num == other.num
    def __lt__(self, other):
        return self.num < other.num

print(Version(1) <= Version(2))  # True, auto-derived
Real-world example A package manager's Version class uses total_ordering to support sorting release versions without writing __le__, __gt__, and __ge__ by hand.

Common follow-ups: Why is total_ordering slower than writing all methods manually?;What happens if __eq__ is missing?

Magic Methods & Operator Overloading;Data Types & Structures
All 15 functools & Functional Programming Tools questions