Python Type Hints

Transcript

1. Type Hints

2. José Padilla

3. Work Training

4. Work Open Source

5. PEP 3107

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7. PEP 484

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9. no type checking happens at runtime

10. static analysis refactoring runtime type checking code generation

11. static analysis refactoring runtime type checking code generation

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13. Common built-in types

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27. Generics

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30. mypy

31. static type checker

32. $ pip install mypy

33. $ python app.py

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35. $ python app.py f 1 Traceback (most recent call last):

    File "app.py", line 12, in <module> print(first(1)) # TypeError File "app.py", line 7, in first return seq[0] TypeError: 'int' object is not subscriptable

36. $ mypy app.py

37. $ mypy app.py main.py:12: error: Argument 1 to "first" has

    incompatible type "int"; expected "Sequence[<nothing>]"
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39. mypy-lang.org

40. Python will remain a dynamically typed language

41. Thanks! jpadilla.com twitter.com/@jpadilla_ github.com/jpadilla