python - 为什么在 Python 中使用 {1} == frozenset({1})？

Question

我觉得奇怪的是，在 Python 中，{1} == frozenset({1}) 的计算结果为 True。 set 和 frozenset 是不同的对象类型，我没有看到其他可迭代对象类型之间的这种相似性(例如 {1} == (1,) 的计算结果为 False)。为什么集合会出现这种行为？是否有其他具有类似行为的可迭代对象类型？

Answer 1

根据 documentation python2和 documentation python3

Instances of set are compared to instances of frozenset based on their members. For example, "set('abc') == frozenset('abc')" returns True.

在 python3 文档中:

Both set and frozenset support set to set comparisons. Two sets are equal if and only if every element of each set is contained in the other (each is a subset of the other). A set is less than another set if and only if the first set is a proper subset of the second set (is a subset, but is not equal). A set is greater than another set if and only if the first set is a proper superset of the second set (is a superset, but is not equal).