Why lambda functions are used in Python - See It in Action

Why lambda functions are used

📖 Scenario: Imagine you have a list of numbers and you want to quickly create a new list with each number doubled. You want to do this without writing a full function because it's a simple task.

🎯 Goal: You will learn how to use a lambda function to double numbers in a list using the map() function.

📋 What You'll Learn

Create a list called numbers with the values 1, 2, 3, 4, 5

Create a lambda function that doubles a number

Use the map() function with the lambda to double each number in numbers

Convert the result of map() to a list called doubled_numbers

Print the doubled_numbers list

💡 Why This Matters

🌍 Real World

Lambda functions are used when you need a quick, small function for simple tasks like transforming data in lists.

💼 Career

Many jobs require processing data quickly and cleanly. Lambda functions help write concise code for data manipulation and functional programming.

1

Create the list of numbers

Create a list called numbers with these exact values: 1, 2, 3, 4, 5

Python

# Create the list called numbers with values 1, 2, 3, 4, 5
# Your code here

Need a hint?

Use square brackets [] to create a list and separate numbers with commas.

2

Create a lambda function to double a number

Create a lambda function called double that takes one argument x and returns x * 2

Python

numbers = [1, 2, 3, 4, 5]
# Create a lambda function called double that doubles its input
# Your code here

Need a hint?

A lambda function is written as lambda arguments: expression.

3

Use map() with the lambda function

Use the map() function with the double lambda and the numbers list. Convert the result to a list called doubled_numbers

Python

numbers = [1, 2, 3, 4, 5]
double = lambda x: x * 2
# Use map() with double and numbers, then convert to list called doubled_numbers
# Your code here

Need a hint?

The map() function applies a function to each item in a list.

4

Print the doubled numbers

Print the list doubled_numbers to see the doubled values

Python

numbers = [1, 2, 3, 4, 5]
double = lambda x: x * 2
doubled_numbers = list(map(double, numbers))
# Print doubled_numbers
# Your code here

Need a hint?

Use print() to show the list on the screen.