在Python中定义类型字典

Question

我正在尝试在Python中定义类型化的字典。我已经编写了以下代码段，但我想知道是否有更好的方法可以实现相同的目标。我正在使用defaultdict，但可以根据需要随时将其更改为dict。

from collections import defaultdict

class typed_dict(defaultdict):

    def __init__(self, key_type, val_type, *args, **kwargs):
        self.key_type = key_type
        if type(val_type) == type(lambda: 1):
            self.val_type = type(val_type())
        else:
            self.val_type = val_type
        super(typed_dict, self).__init__(val_type, *args, **kwargs)

    def __getitem__(self, k):
        try:
            assert type(k) == self.key_type
            return super(typed_dict, self).__getitem__(k)
        except AssertionError:
            print('key mismatch, got {}, must be {}'.format(type(k), self.key_type))

    def __setitem__(self, k, v):
        try:
            assert type(k) == self.key_type
            assert type(v) == self.val_type
            super(typed_dict, self).__setitem__(k, v)
        except AssertionError:
            print('key or value mismatch, got {}: {}, \
 must be {}: {}'.format(type(k), type(v), self.key_type, self.val_type))



d = typed_dict(int, str)
d[1]
d[2] = "two"
d["one"]
d["three"] = 3
d[3] = 3
print(d)

d = typed_dict(int, lambda: '')
d[1]
d[2] = "two"
d["one"]
d["three"] = 3
d[3] = 3
print(d)

import numpy as np
d = typed_dict(int, lambda: np.zeros(2))
d[1]
d[2] = "two"
d[3] = np.array([1,2,3])
print(d)