Cheatsheet de Python para Desarrolladores: Sintaxis, Colecciones y Lambdas

# Square even numbers
squares = [x**2 for x in range(10) if x % 2 == 0]
# Output: [0, 4, 16, 36, 64]

# Dictionary comprehension
squares_map = {x: x**2 for x in range(5)}
# Output: {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}

def handle_command(command):
    match command.split():
        case ["load", filename]:
            return f"Loading data from {filename}"
        case ["save", filename]:
            return f"Saving data to {filename}"
        case ["quit" | "exit"]:
            return "Exiting runtime"
        case _:
            return "Unknown command"

# Reading files automatically closing file handles
with open('dataset.csv', 'r', encoding='utf-8') as f:
    for line in f:
        process(line.strip())

# Custom context manager
from contextlib import contextmanager

@contextmanager
def timer():
    import time
    start = time.perf_counter()
    yield
    print(f"Elapsed: {time.perf_counter() - start:.4f}s")