Deborah Swanson wrote:
But I think you got it right in your last sentence below. defaultdict copied them because they were immutable,
No, definitely not. A defaultdict will never take it upon itself to copy an object you give it, either as a key or a value. The copying, if any, must have occurred somewhere else, in code that you didn't show us. Can you show us the actual code you used to attempt to update the namedtuples? -- Greg -- https://mail.python.org/mailman/listinfo/python-list