以pythonic方式编写复杂循环

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9]
squared_evens = [x**2 for x in numbers if x % 2 == 0]
print(squared_evens)  # 输出: [4, 16, 36, 64]

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9]
squared_evens_gen = (x**2 for x in numbers if x % 2 == 0)
print(list(squared_evens_gen))  # 输出: [4, 16, 36, 64]

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9]
squared_evens_map_filter = list(map(lambda x: x**2, filter(lambda x: x % 2 == 0, numbers)))
print(squared_evens_map_filter)  # 输出: [4, 16, 36, 64]

import itertools

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9]
squared_evens_itertools = list(itertools.starmap(lambda x: x**2, filter(lambda x: x % 2 == 0, numbers)))
print(squared_evens_itertools)  # 输出: [4, 16, 36, 64]

def is_even(x):
    return x % 2 == 0

def square(x):
    return x**2

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9]
squared_evens = [square(x) for x in numbers if is_even(x)]
print(squared_evens)  # 输出: [4, 16, 36, 64]