Python min() function returns the smallest element in a collection of items (list, tuple, set, string, or other iterables) or among multiple arguments.

 

numbers_list = [7, 1, 3, 5]

print('The smallest number from numbers_list is:', min(numbers_list))

# Output: The smallest number from numbers_list is: 1

As you can see, it returns the lowest value from the iterable.

It compares items using the < operator by default, but can be customized with a key function.

If the iterable is empty and no default value is provided, it raises a ValueError.

Syntax

min(iterable, key, default)

Parameters

Argument	Description
iterable	It represents an iterable, one or more elements to compare. It iterates over this to find the minimum.
key (optional)	It represents a callable function that accepts a single argument and returns a value used for comparison.
default (optional, default not set; iterable form only)	It is a default value that is returned if the iterable is empty. If omitted and the iterable is empty, it will throw ValueError.

With a Key Function

We can use a key function to set the criteria for finding the minimum value.

 

data = [{"name": "Jon", "age": 28},
        {"name": "Mark", "age": 25}]

youngest_person = min(data, key=lambda x: x['age'])

print(youngest_person)

# Output: {'name': 'Mark', 'age': 25}

In this code, we find the minimum value based on a person’s age. Since Mark is 25 years old, we get a dictionary with the lowest age.

Individual elements

As we know, we can pass multiple arguments to the min() function, and it will return the minimum element from them.

smallest_number = min(8, 4, 17, 5)

print("The smallest number is:", smallest_number)

# Output: The smallest number is: 4

With Strings (Lexicographical Order)

The min() function returns the string that is smallest in lexicographical (i.e., alphabetical) order.

It compares strings alphabetically (case-sensitive; uppercase letters appear before lowercase letters).

smallest_string = min("Ford", "Tesla", "Audi")

print("The smallest string is:",smallest_string)

# Output: The smallest string is: Audi

In the first step, it compares “Ford” vs “Tesla” and the First letters: “F” (Unicode 70) vs “T” (Unicode 84). Since 70 < 84, “Ford” is smaller than “Tesla”.

In step two, it compares “Ford” vs “Audi” in which the first letters: “F” (70) vs “A” (65). Since 65 < 70, “Audi” is smaller.

Handling empty iterables

If you pass an empty iterable to min(), it will raise a ValueError.

print(min([]))

# Output: ValueError: min() arg is an empty sequence

To handle this, you can specify a default value using the default parameter.

print(min([], default="Empty"))

# Output: Empty

With Tuples (Element-Wise Comparison)

When you use the min() function on a list of tuples, comparison happens lexicographically, just like how words are compared in a dictionary.

1. Compare the first elements of the tuples.
2. If the first elements are equal, compare the second elements.
3. Continue element by element until a difference is found.

points = [(2, 3), (1, 4), (1, 2)]

min_point = min(points)  # Compares first elements, then second if tied

print(min_point)

# Output: (1, 2)

In the above code, it compares (2, 3) with (1, 4). Now, 2 vs 1 → since 1 < 2, (1, 4) is smaller.

In the next step, it compares (1, 4) with (1, 2). First elements are equal (1 == 1), so compare the second elements. Since 2 < 4, (1, 2) is smaller. That is why (1, 2) is the output.

With Dictionaries

When you call min() on a dictionary, Python doesn’t look at the values by default — it works on the keys.

grades = {"Ankit": 85, "Krunal": 72, "Rushabh": 90}

print(min(grades))

# Output: "Ankit" (lexicographically smallest key)

print(min(grades, key=grades.get))

# Output: "Krunal"   (student with lowest grade)

The min() function finds the smallest key lexicographically (alphabetical order).

“Ankit” < “Krunal” < “Rushabh”, so “Ankit” is in the output.

When it comes to the key=grades.get, it tells Python to compare dictionary keys based on their values (the grades).

Behind the scenes:

1. “Ankit” → 85
2. “Krunal” → 72
3. “Rushabh” → 90

The lowest grade is 72, which belongs to “Krunal”.

That’s all!