Python min() Function

Summary: in this tutorial, you’ll learn how to use the Python min() function to return the smallest item of an iterable or the smallest argument of two or more arguments.

Introduction to the Python min() function

The min() function returns the smallest items of two or more arguments:

min(arg1,arg2,*args[,key])Code language: Python (python)

In this syntax:

• arg1, arg2, .. are the input arguments.
• key is an optional keyword-only parameter that specifies a key for comparing the arguments.

The min() function also accepts an iterable and returns the smallest item of the iterable:

min(iterable, *[, key, default])Code language: Python (python)

In this syntax:

• iterable is the input iterable.
• key is an optional keyword-only argument that specifies the key for comparing the items of the iterable.
• default is an optional keyword-only argument that specifies a value that the min() function returns if the iterable is empty. If the iterable is empty and the default argument is omitted, the min() function raises a ValueError exception.

If multiple items are minimal, the min() function returns the first one it encounters.

Python min() function examples

Let’s take some examples of using the Python min() function.

1) Using the Python min() function to find the minimum argument between multiple arguments

The following example uses the min() function to get the smallest numbers:

result = min(1, 2, 3)
print(result) # 1Code language: Python (python)

If you pass multiple strings, the min() function returns the minimum string based on alphabetical order:

result = min('John', 'Alice', 'Jane')
print(result) # AliceCode language: Python (python)

The following example shows how to use the min() function with user-defined objects:

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def __str__(self):
        return f'Name:{self.name}, age:{self.age}'


result = min(
    Person('John', 21),
    Person('Alice', 22),
    Person('Jane', 20),
    key=lambda p: p.age
)

print(result)Code language: Python (python)

Output:

Name:Jane, age:20Code language: Python (python)

How it works.

First, define the Person class with two attributes, name and age:

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def __str__(self):
        return f'Name:{self.name}, age:{self.age}'Code language: Python (python)

Second, use the min() function to find the person with the smallest age:

result = min(
    Person('John', 21),
    Person('Alice', 22),
    Person('Jane', 20),
    key=lambda p: p.age
)Code language: Python (python)

Besides passing the Person objects, we also specify the age as the key to comparing these Person objects.

2) Using the Python min() function to find the minimum item of an iterable

The following example uses the min() function to find the smallest number of a list:

scores = [1, 5, 3, 2]
min_score = min(scores)
print(min_score)  # 1Code language: Python (python)

Similarly, this example uses the min() function to find the minimum name based on alphabetical order:

names = ['John', 'Alice', 'Jane']
name = min(names)
print(name)  # AliceCode language: Python (python)

This example illustrates how to use the min() function to find the youngest person:

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def __str__(self):
        return self.name


people = (
    Person('John', 21),
    Person('Alice', 22),
    Person('Jane', 20)
)

youngest_person = min(people, key=lambda p: p.age)
print(youngest_person)Code language: Python (python)

Output:

Name:Jane, age:20Code language: Python (python)

In this example, we pass a list of Person objects and use the min() function to find the youngest person who has the smallest age.

Summary

• Use the min() function to find the minimum item of arguments or of items in an iterable.
• Use the key parameter to specify the key to compare the objects.