Python List Comprehensions and Generators

Python List Comprehensions and Generators

Master Python list comprehensions and generators for efficient, readable code.

List Comprehensions

Basic Syntax

# Traditional way
squares = []
for x in range(10):
    squares.append(x**2)

# List comprehension
squares = [x**2 for x in range(10)]

With Condition

even_squares = [x**2 for x in range(10) if x % 2 == 0]

Nested Comprehensions

matrix = [[i*j for j in range(3)] for i in range(3)]

Generators

Generator Expressions

squares_gen = (x**2 for x in range(10))
for square in squares_gen:
    print(square)

Generator Functions

def fibonacci():
    a, b = 0, 1
    while True:
        yield a
        a, b = b, a + b

Benefits

• Memory Efficient: Generators don't store all values
• Readable: More concise than loops
• Fast: Optimized for performance
• Pythonic: Follows Python best practices

When to Use

• List comprehensions for small datasets
• Generators for large datasets or infinite sequences
• Both for cleaner, more readable code