Python functools total_ordering() Function

The Pythontotal_ordering() function decorator from the functools module simplifies the implementation of all comparison methods. The functools module is designed to specify the higher-order functions, and the total ordering decorator is a prime example. It enhances the class capabilities without requiring explicit definitions for each comparison method, making the code more maintainable and efficient.

Syntax

Following is the syntax for thetotal_ordering() function.

@total_ordering()

Parameters

This function doesn't accept any parameters.

Return Value

The decorator returns the class with the additional comparison methods like (__le__, __gt__, __ge__).Below example demosntr

Example 1

The example below, demonstrates a class with methods like __le__, __gt__ and __ge__, which are automatically provided by thetotal_ordering decorator.

from functools import total_ordering@total_orderingclass Num:    def __init__(self, val):        self.val = val    def __eq__(self, other):        return self.val == other.val    def __lt__(self, other):        return self.val < other.valprint(Num(31) < Num(12)) print(Num(200) > Num(101)) print(Num(56) == Num(18))print(Num(2) != Num(2))

Output

The result is generated as follows −

FalseTrueFalseFalse

Example 2

In this example, the total_ordering() decorator compares word object on the length of their text. By defining the __eq__ and __it__ methods, it automatically provides other comparison methods,simplifying the comparison logic.

from functools import total_ordering@total_orderingclass Word:    def __init__(self, txt):        self.txt = txt    def __eq__(self, other):        return len(self.txt) == len(other.txt)    def __lt__(self, other):        return len(self.txt) < len(other.txt)print(Word("grapes") < Word("watermelon"))  print(Word("banana") < Word("kiwi"))     print(Word("pineapple") == Word("grape"))

Output

The code is generated as follows −

TrueFalseFalse

Example 3

We are now creating a code that defines a point class with n and p coordinates. Using thetotal_ordering() decorator, function simplifies the code by defining the __eq__ and __lt__ methods. The decorator allows easy comparison of point objects based on their coordinates.

from functools import total_ordering@total_orderingclass Point:    def __init__(self, n, p):        self.n = n        self.p = p    def __eq__(self, other):        return (self.n, self.p) == (other.n, other.p)    def __lt__(self, other):        return (self.n, self.p) < (other.n, other.p)print(Point(31, 4) < Point(21, 11)) print(Point(10, 12) > Point(0, 13)) print(Point(2, 2) == Point(1, 1))

Output

The output is obtained as follows −

FalseTrueFalse