How Can I Efficiently Return Multiple Values from a Python Function?

Alternatives for Returning Multiple Values from a Python Function

A common issue in programming is the need to return multiple values from a function. Several methods offer solutions to this problem, each with its pros and cons.

Tuples

Tuple is a straightforward option for returning multiple values while keeping them in a specific order. However, as the number of values returned increases, tuple becomes cumbersome and error-prone.

Dictionaries

Dictionaries provide a more structured approach, allowing you to project out individual values using keys. They offer a solution similar to namedtuples from C.

Classes

Creating a specialized class allows for the return of custom structures. This method provides flexibility but may involve more boilerplate code in defining the class. Python's __slots__ attribute can optimize space by eliminating the __dict__ overhead.

Data Classes (Python 3.7 )

Data classes offer a concise way to create classes with built-in special methods and type annotations, simplifying the creation of return structures.

Lists

Bill the Lizard proposes using lists, although this method isn't commonly favored due to the potential for mixed-type elements and the lack of significant advantages over tuples in Python.

Named Tuples (Preferred Method)

For a concise and well-organized approach, Python's named tuples (added in 2.6) are highly recommended. They combine the order and ease of tuples with the ability to access values by name.

Example Using Named Tuples:

import collections

Point = collections.namedtuple('Point', ['x', 'y'])
p = Point(1, y=2)

print(p.x, p.y)  # Output: 1 2

Named Tuple Using Python 3's Typing Library:

from typing import NamedTuple

class Employee(NamedTuple):
    name: str
    id: int = 3  # default value

employee = Employee('Guido')
print(employee.id)  # Output: 3

Ultimately, the best method for returning multiple values depends on the specific requirements and code organization. Named tuples offer a balance of simplicity and structured access, making them a popular and versatile solution for this common problem.

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