![Syntax: Using Generics
from typing import List, Set, Dict, Tuple
my_var: List[int] = [1]
my_var: Tuple[int, str] = (1, 'hello')
my_var: Set[int] = {6, 7}
my_var: Dict[int, str] = {6: 'six', 7: 'seven'}
from typing import List, Union, Optional
my_var: List[Union[int, str]] = [3, 5, "test", "fun"]
my_var: Optional[str] = None
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![Syntax: Classes
from typing import List
class MyClass:
charge_percent: int = 100
def __init__(self, items: List[str]) -> None:
self.items = items
def my_method(self, num: int, str1: str) -> str:
return num * str1
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Static type checking in python
- 1. Static Type Checking in Python Sebastian Wagner, swagner@suse.com Ceph component lead 1 / 19
- 2. Where is the Problem?Where is the Problem? 2 / 192 / 19
- 3. In a nutshell Static typing vs. dynamic typing Type annotations mypy - http://mypy-lang.org/ 3 / 19
- 4. Would I bene t from static typing? Project is large or complex. code base must be maintained for a long time. Multiple developers are working on the same code You're learning Python. 4 / 19
- 5. Where can static typing help? Correct arguments to functions and operators Spelling mistakes Type compatibility check None - a loophole in the type system API Documentation Editor support 5 / 19
- 6. Editor support Error Highlighting: Parameter Documentation 6 / 19
- 7. Editor support (2) Code Completion: 7 / 19
- 8. Of course, it has limitations.Of course, it has limitations. 8 / 198 / 19
- 10. Syntax: Functions def stringify(num: int) -> str: return str(num) def add(num1: int, my_float: float = 3.5) -> float: return num1 + my_float add(1, 'string') Running mypy reveals: error: Argument 2 to "add" has incompatible type "str"; expected "float" 10 / 19
- 11. Syntax: Variables my_var: int = 1 my_var: float = 1.0 my_var: bool = True my_var: str = "test" my_var: bytes = b"test" 11 / 19
- 12. Syntax: Using Generics from typing import List, Set, Dict, Tuple my_var: List[int] = [1] my_var: Tuple[int, str] = (1, 'hello') my_var: Set[int] = {6, 7} my_var: Dict[int, str] = {6: 'six', 7: 'seven'} from typing import List, Union, Optional my_var: List[Union[int, str]] = [3, 5, "test", "fun"] my_var: Optional[str] = None 12 / 19
- 13. Syntax: Classes from typing import List class MyClass: charge_percent: int = 100 def __init__(self, items: List[str]) -> None: self.items = items def my_method(self, num: int, str1: str) -> str: return num * str1 13 / 19
- 14. Syntax: Escape routes from typing import Any my_var: Any = mystery_function() my_var = confusing_function() # type: ignore Don't confuse with object! Forward References def f(foo: 'A') -> int ... class A: ... 14 / 19
- 15. Syntax: Python 2 def add(num1, my_float = 3.5): # type: (int, float) -> float return num1 + my_float my_var = 'hello' # type: str 15 / 19
- 16. Stub les Interface file for type hints only .pyi Cython bindings Native code typeshed 16 / 19
- 17. Legacy Code Generate type annotations pyannotate MonkeyType Focus on modules that are imported often. Write a script that runs mypy on the whole code base 17 / 19
- 18. Questions?Questions? 18 / 1918 / 19
- 19. Thank youThank you 19 / 1919 / 19