Description

xandrade

opened on Apr 18, 2022

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Documentation

Found that the typing List is used in example, but import is missed at dataclasses.rst file.

In this example:

  @dataclass
  class D:
      x: List = []
      def add(self, element):
          self.x += element

the import from typing import List is missing

Activity

1. xandrade

   added

   docsDocumentation in the Doc dirDocumentation in the Doc dir

   on Apr 18, 2022
2. ericvsmith commented on Apr 18, 2022

   

   ericvsmith

   on Apr 18, 2022

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   I'm not sure how important this is. The example already says the code isn't valid. Maybe just use "list" instead of "List".

   Reacted by Jelle Zijlstra and Shantanu
3. xandrade commented on Apr 18, 2022

   

   xandrade

   on Apr 18, 2022

   ContributorAuthor

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   Sure @ericvsmith, but the example in the documentation doesn't run.
   Your suggestion for using list instead of list works, as long it is defined as x: list = field(default_factory=list).
   However, I think the example is about forcing the datatype in the list using List from typing.

   This works (as example only):

   from dataclasses import dataclass
   from typing import List
   
   @dataclass
   class User:
       x: list = field(default_factory=list)
       y: List[int] = field(default_factory=list)
   

   this doesn't work

   from dataclasses import dataclass
   
   @dataclass
   class User:
       x: list = []
   
4. xandrade

   closed this as completedon Apr 19, 2022

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