Question

我正在学习python。我试图做出“字典理解”。我很困惑，为什么python告诉我“船尾”是集合而不是字典。

# dictionary<string, tuple<string, string>>
DATA = {
    'A': (
        ('Label1', 'Category1'),
        ('Label2', 'Category1'),
        ('Label3', 'Category2'),
        ('Label4', 'Category2'),
    ),
    'B': (
        ('Label1', 'Category1'),
        ('Label2', 'Category1'),
        ('Label3', 'Category2'),
        ('Label4', 'Category2'),
    ),
    'C': (
        ('Label1', 'Category1'),
        ('Label2', 'Category1'),
        ('Label3', 'Category2'),
        ('Label4', 'Category2'),
    ),
    'D': (
        ('Label1', 'Category1'),
        ('Label4', 'Category2'),
    )
}


class Poop:
    def __init__(self, label, category):
        self.label = label
        self.category = category


def main():

    my_dictionary = {'A': 1, 'B': 2}
    print "{}".format(type(my_dictionary))

    poops = {
        (label, Poop(label, category))
        for label, category in DATA['A']
    }

    print "{}".format(type(poops))
    for _, poop in poops:
        print "{}".format(type(poop))


if __name__ == "__main__":
    main()

输出：

pydev debugger: process 1008 is connecting

Connected to pydev debugger (build 191.6605.12)
<type 'dict'>
<type 'set'>
<type 'instance'>
<type 'instance'>
<type 'instance'>
<type 'instance'>

Process finished with exit code 0

Answer 1

因为您在理解中使用了一个元组，所以它会创建一组元组{（k，v）}，其中k和v是键和值。

我认为您想要的是：

poops = {label:Poop(label, category) for label, category in DATA['A'].items()}

主要区别是{k：v for ...}与{（k，v）for ...}

字典理解-调试器为什么告诉我我的字典是集合？

1 个答案: