a = dict(one=1, two=2, three=3)
b = {‘one‘: 1, ‘two‘: 2, ‘three‘: 3}
c = dict(zip([‘one‘, ‘two‘, ‘three‘], [1, 2, 3]))
d = dict([(‘two‘, 2), (‘one‘, 1), (‘three‘, 3)])
e = dict({‘three‘: 3, ‘one‘: 1, ‘two‘: 2})
print(a == b == c == d == e) # True
from collections import abc
print(isinstance(a, abc.Mapping)) # True
# 1. The main value of the ABCs is documenting and formalizing the
# minimal interfaces for mappings, and serving as criteria for isinstance
# tests in code that needs to support mappings in a broad sense.
print(hash((1, 2, (3, 4)))) # -2725224101759650258
# 1. An object is hashable if it has a hash value which never changes
# during its lifetime (it needs a __hash__() method), and can be compared
# to other objects (it needs an __eq__() method).
# 2. Hashable objects which compare equal must have the same hash value.
# 3. (atomic immutable types / frozen set / tuple when all its items are hashable)
# 4. User-defined types are hashable by default because their hash value is their
# id() and they all compare not equal. If an object implements a custom __eq__
# that takes into account its internal state, it may be hashable only if all its
# attributes are immutable.
原文：https://www.cnblogs.com/lb477/p/10925072.html