Re: [Python-Dev] PySequence_Check but no __len__

2018年6月22日 12:10:11 -0700

On 6/22/2018 7:17 AM, Christian Tismer wrote:
My problem is to find out how to deal with a class which has
__getitem__ but no __len__.
The documentation suggests that the length of a sequence can always
be obtained by len().
https://docs.python.org/3/reference/datamodel.html
It says that plainly: "The built-in function len() returns the number of items of a sequence. "
https://docs.python.org/3/library/collections.abc.html#collections-abstract-base-classes
says that a Sequence has both __getitem__ and __len__.
I am surprised that a C-API function calls something a 'sequence' without it having __len__.
--
Terry Jan Reedy
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