Are containers always iterable?

问题

Is there a scenario where the container is not iterable, according to this graph?

回答1:

Depends on what you mean by always. According to collections.abc

• a container is an object that implements __contains__ method
• an iterable is an object that implements __iter__ (or __getitem__, as a fallback)

So, theoretically, no, you can implement a container that is not an iterable. However, all standard python containers (and most containers implemented by libraries) are also iterable.

来源：https://stackoverflow.com/questions/56989687/are-containers-always-iterable