Lesson 4.3: Lambda Functions (Anonymous Functions in Python)

Introduction:
Lambda functions are small, anonymous, one-line functions in Python. They are useful when you need a simple function for a short task and do not want to define a full function using def. Lambda functions help make your code concise and readable, especially when used with functions like map(), filter(), and reduce().

1. Syntax of Lambda Functions:

Example – Simple Lambda Function:

Output:

Explanation:

• a and b are input arguments

• The expression a + b is evaluated and returned

• No need to use return keyword

2. Lambda with map():

• map() applies a function to each item in a list or sequence.

Output:

3. Lambda with filter():

• filter() filters elements based on a condition.

Output:

4. Lambda with reduce():

• reduce() (from functools module) applies a function cumulatively to items of a sequence.

Output:

Practical Tips:

• Use lambda functions for simple tasks; avoid using them for complex logic

• Ideal for short operations passed as arguments to other functions

• Keep code readable and avoid overusing lambda in large programs

Learning Outcome of This Lesson:

• Understand what lambda functions are and when to use them

• Write concise one-line functions using lambda

• Apply lambda functions with map(), filter(), and reduce()

• Improve code efficiency for small, reusable operations