min()

The built-in min() function allows you to find the smallest value in an iterable or among multiple arguments. This function is versatile and can handle various data types, including numbers, strings, and more:

Python 
>>> min([3, 5, 9, 1, -5])
-5

min() Signatures

Python Syntax 
min(iterable, *, key=None)
min(iterable, *, default, key=None)
min(arg1, arg2, *args, key=None)

Arguments

Argument Description Default Value
iterable An iterable object, such as a list, tuple, dictionary, or string. Required argument
default A value to return if the iterable is empty. Keyword-only argument
key A single-argument function to customize the comparison criteria. None
*args An undefined number of arguments. -

Return Value

  • With a single iterable, min() returns the smallest item.
  • With multiple arguments, min() returns the smallest of the provided arguments.
  • If default is provided and the iterable is empty, the default value is returned.

min() Examples

With a list of integers as an argument:

Python 
>>> min([3.4, 5, 9, 1.2, -5])
-5

With a string as an argument:

Python 
>>> min("abcdefghijklmnopqrstuvwxyz")
'a'

With multiple string arguments:

Python 
>>> min("banana", "apple", "cherry")
'apple'

min() Common Use Cases

The most common use cases for the min() and max() functions include the following:

  • Finding the smallest number in a series of numbers.
  • Identifying the earliest strings alphabetically.
  • Extracting the minimum value from dictionary keys or values.
  • Clipping values to a specified range in data processing.

min() Real-World Example

Suppose you have a dictionary of product prices, and you want to identify the cheapest product. You can use min() with the .items() method and a lambda function as the key argument:

Python 
>>> prices = {
...    "banana": 1.20,
...    "pineapple": 0.89,
...    "apple": 1.57,
...    "grape": 2.45,
... }

>>> min(prices.items(), key=lambda item: item[1])
('pineapple', 0.89)

This example demonstrates how min() can help you identify the least expensive products by using the dictionary’s values for comparison.

min() in Custom Classes

You can support min() in custom classes by implementing the .__lt__() special methods. Here’s a quick example:

Python person.py 
from datetime import date

class Person:
    def __init__(self, name, birth_date):
        self.name = name
        self.birth_date = date.fromisoformat(birth_date)

    def __repr__(self):
        return (
            f"{type(self).__name__}"
            f"({self.name}, {self.birth_date.isoformat()})"
        )

    def __lt__(self, other):
        return self.birth_date > other.birth_date

# Usage
jane = Person("Jane Doe", "2004-08-15")
john = Person("John Doe", "2001-02-07")

print(min(jane, john))  
# Output: Person(Jane Doe, 2004-08-15)

This implementation allows you to use min() and max() on instances of the Person class, comparing them by birthdate.

Python's min() and max(): Find Smallest and Largest Values

Tutorial

Python's min() and max(): Find Smallest and Largest Values

In this tutorial, you'll learn how to use Python's built-in min() and max() functions to find the smallest and largest values. You'll also learn how to modify their standard behavior by providing a suitable key function. Finally, you'll code a few practical examples of using min() and max().

basics python

For additional information on related topics, take a look at the following resources:

By Leodanis Pozo Ramos • Updated Nov. 7, 2024 • Reviewed by Dan Bader
Python’s Built-in Functions Share Feedback