类型错误：不能腌制 dict_items 对象

Question

为什么

pickle.dumps({}.items())

TypeError: can't pickle dict_items objects在 Python 3.5.2 中失败，但在 Python 2.7.12 中没有？

“腌制”字典

pickle.dumps({})

适用于两个 Python 版本（并且在 Python 2.7.12 中提供与上述命令相同的输出）。

Answer 1

because in python 2.7 .items() returns a mere list of tuples, which is picklable.

In python 3.x it returns a dict_items object (that doesn't exist in python 2), not picklable (but faster since it doesn't generate a list, it's the rough equivalent of python 2.x iteritems()).

But you can force list conversion to simulate python 2.x behaviour:

pickle.dumps(list(d.items()))