python 简化以下代码根据我的输入修改数字生成的长度并将数字和英文组合起来 digits = 0123456789 combinations_num = for i in digits for j in digits for k in digits for l in digits

def generate_combinations(length): digits = '0123456789' letters = string.ascii_lowercase combinations = {} for _ in range(length): for i in digits+letters: for j in digits+letters: combination = i + j if combination not in combinations: combinations[combination] = True return combinations.keys()

print(generate_combinations(4))