Lambda functions are small functions that are restricted to a single expression in Python. These are also known as anonymous functions and are declared with no function name. This makes them useful in places where you need a small, one-off function that you won’t reuse elsewhere in your code.
In this post, I’ll share some examples and exercises that will help you understand lambda functions in Python better. Let’s dive right in.
1. A simple lambda function
square = lambda x: x ** 2
print(square(5))Output:
2. Lambda function with multiple arguments
multiply = lambda x, y: x * y
print(multiply(3, 7))Output:
3. Using a lambda function inside another function
def my_func(n):
return lambda x: x * n
doubler = my_func(2)
print(doubler(5))Output:
4. Using lambda with Python built-in functions
my_list = [1, 2, 3, 4, 5, 6]
odd_numbers = list(filter(lambda x: x % 2 != 0, my_list))
print(odd_numbers)Output:
5. Using lambda function for sorting
my_list = [("apple", 50), ("banana", 10), ("cherry", 30)]
sorted_list = sorted(my_list, key=lambda x: x[1])
print(sorted_list)Output:
6. Using a lambda function to return a function
def my_func(n):
return lambda x: x + n
adder = my_func(5)
print(adder(10))Output:
7. Using a lambda function in list comprehension
my_list = [1, 2, 3, 4, 5, 6]
new_list = [(lambda x: x ** 2)(x) for x in my_list]
print(new_list)Output:
8. Using a lambda function to sort a list of strings by the last character
my_list = ["apple", "banana", "cherry"]
sorted_list = sorted(my_list, key=lambda x: x[-1])
print(sorted_list)Output:
9. Using a lambda function with the reduce function
from functools import reduce
my_list = [1, 2, 3, 4, 5]
product = reduce((lambda x, y: x * y), my_list)
print(product)Output:
10. Using a lambda function with the map function
my_list = [1, 2, 3, 4, 5]
new_list = list(map(lambda x: x ** 2, my_list))
print(new_list)Output:
I hope these exercises and examples give you a better understanding of lambda functions in Python. Check out my post on 15 Python Object-Oriented Programming (OOP) Exercises.
