Lambda Functions

A lambda function is a small, anonymous function in Python, created using the lambda keyword. It's ideal for quick, one-time operations without needing a full def function.

🔧 Syntax:

lambda arguments: expression

• Takes any number of arguments, but only one expression.

• Automatically returns the value of the expression.

💡 Example: Square a Number

square = lambda x: x * x
print(square(5))  # Output: 25

🔄 Use in map(), filter(), and sorted()

nums = [1, 2, 3, 4]

# Squaring each number
squares = list(map(lambda x: x**2, nums))
print(squares)  # [1, 4, 9, 16]

🔍 More Examples:

Filter even numbers:

evens = list(filter(lambda x: x % 2 == 0, nums))
print(evens)  # [2, 4]

Sort list of tuples by second item:

pairs = [(1, 3), (2, 1), (4, 2)]
sorted_pairs = sorted(pairs, key=lambda x: x[1])
print(sorted_pairs)  # [(2, 1), (4, 2), (1, 3)]

💡 Real-Life Analogy:

Think of a lambda like a sticky note with a quick formula — small, disposable, and used instantly when needed.