带有元组键的msgpack字典

Question

import msgpack
path = 'test.msgpack'
with open(path, "wb") as outfile:
    outfile.write(msgpack.packb({ (1,2): 'str' }))

现在一切正常

with open(path, 'rb') as infile:
    print(msgpack.unpackb(infile.read()))

错误

Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "msgpack/_unpacker.pyx", line 195, in msgpack._cmsgpack.unpackb
ValueError: list is not allowed for map key

（只有在拆包时才会检测到错误，这不是很奇怪吗？）

如何编写或解决msgpacking一个以元组为键的python dict

Answer 1

这里有两个问题：msgpack在默认情况下使用strict_map_key=True，因为版本1.0.0（source）和msgpack的数组被隐式转换为Python的lists，这是不可散列的。要使工作正常，请传递所需的关键字参数：

with open(path, "rb") as f:
    print(msgpack.unpackb(f.read(), use_list=False, strict_map_key=False))

# outputs: {(1, 2): 'str'}