I would've expected Python's keys method to return a set instead of a list. Since it most closely resembles the kind of guarantees that keys of a hashmap would give. Specifically, they are unique and not sorted, like a set. However, this method returns a list:
我希望Python的key方法返回一个集合而不是列表。因为它最类似于hashmap的键所提供的保证。具体来说，它们是唯一的，没有排序，就像一组。但是，此方法返回一个列表：
>>> d = {}
>>> d.keys().__class__
<type 'list'>
Is this just a mistake in the Python API or is there some other reason I am missing?
这只是Python API中的一个错误，还是我还缺少其他原因？
1 个解决方案
#1
62
One reason is that dict.keys() predates the introduction of sets into the language.
一个原因是dict.keys（）早于将集合引入语言。
Note that the return type of dict.keys() has changed in Python 3: the function now returns a view rather than a list.
请注意，dict.keys（）的返回类型在Python 3中已更改：该函数现在返回视图而不是列表。
#1
62
One reason is that dict.keys() predates the introduction of sets into the language.
一个原因是dict.keys（）早于将集合引入语言。
Note that the return type of dict.keys() has changed in Python 3: the function now returns a view rather than a list.
请注意，dict.keys（）的返回类型在Python 3中已更改：该函数现在返回视图而不是列表。