Python Basics: Lambdas

 

Lambdas in Python are like mini-functions without a name, perfect for short, quick operations—think of them as the “Post-it notes” of the coding world: compact, purposeful, and disposable.

What Is a Lambda Function?

A lambda in Python is an anonymous function defined using the lambda keyword. It’s used when you need a simple function for a short period and don’t want to formally define it with def.

Syntax Breakdown

lambda arguments: expression

• You can pass multiple arguments, but only a single expression.
• You can’t use statements like loops or conditionals—just expressions.

def traditional_square(num):
    return num * num

square = lambda num: num * num  #defined the function
print(square(5))

Common Use Cases

Use Case	Example
With map()	map(lambda x: x*2, [1, 2, 3]) → [2, 4, 6]
With filter()	filter(lambda x: x > 0, [-1, 0, 1]) → [1]
With sorted()	sorted(words, key=lambda x: len(x)) → sort by length
Quick function	lambda x, y: x + y