python dict理解有两个范围

Question

我正在尝试生成一些代码,例如:

{1:7,2:8,3:9,4:10}

和

{i:j for i in range(1,5) for j in range(7,11)}

产生

{1: 10, 2: 10, 3: 10, 4: 10}

我该怎么解决？

谢谢

Answer 1

使用zip:

>>> dict(zip(range(1,5), range(7,11)))
{1: 7, 2: 8, 3: 9, 4: 10}

使用dict理解:

>>> {k:v for k, v in zip(range(1,5), range(7,11))}
{1: 7, 2: 8, 3: 9, 4: 10}

>>> {x:x+6 for x in range(1,5)}
{1: 7, 2: 8, 3: 9, 4: 10}

为什么你的代码不起作用:

您的代码类似于以下代码:

ret = {}
for i in range(1,5):
    for j in range(7,11):
        ret[i] = j
    # ret[i] = 10 is executed at last for every `i`.