python - 如果 x 在 dict.iterkey() 中，则 y 是 dict.value

Question

我想知道如何迭代多个列表，将值与字典中的键匹配，然后创建一个等于这些值的新列表。

我是堆栈和Python的新手，所以我们将不胜感激。

X1 = [1, 2, 3, 5, 4]
X2 = [3, 2, 2, 5, 1]
X3 = [2, 4,  3,  1,  5]

Y1 = []
Y2 = []

Z = {1:20, 2:19, 3:18, 4:17, 5:16}

def num_maker(num_list, new_list):
    for nums in num_list:
        if nums in Z.iterkeys():
            for newnums in new_list:
                new_list = Z.value(nums)

num_maker(X1, Y1)

Answer 1

如果您有兴趣学习如何在没有@Joachim Isaksson 提供的列表理解的情况下执行此操作

这是您需要执行的操作:

# Your number list
X1 = [1, 2, 3, 5, 4]

# Your dictionary with keys from the number list
Z = {1:20, 2:19, 3:18, 4:17, 5:16}

# Expected output list should be: [20,19,18,16,17] based on X1

def num_maker(num_list, dictionary_of_num_list):

    # Initialize empty list
    list_to_return = []
    # Loop over your num_list
    for number in num_list:
        # Access the dictionary using the list's current element as the key and then append it to a new list which you can return
        list_to_return.append(dictionary_of_num_list.get(number))

    return list_to_return

print(num_maker(X1, Z))

输出:

[20, 19, 18, 16, 17]

您希望 Y1 作为输出列表，因此您可以这样做:

Y1 = num_maker(X1, Z)

希望这有帮助。使用 python 3 而不是 python 2 运行它。