为什么 print(zip(*A)), 给 output 形式<zip object at 0x7f8ef0f82b48> ，但在执行 set(zip(*A)) 时预期 output？ 注意 A 是一个列表</zip>

Question

I do understand this is an object, but can you throw some insights on how it is able to map to different lists?

Answer 1

In Python, the zip functions returns a custom iterator object that computes each tuple of items from the sequence it is given lazily. This object has no __repr__ method, so printing it produces the default <zip object at <address>> . The set constructor then evaluated the created iterator, creating a set of tuples. Sets do have a __repr__ , so printing the set will produce the expected output.