i have 2 optional fields publish and ratings, here is my code
class POST(BaseModel):
title: str
content: str
published: bool = True
rating: Optional[int] = None
They both result in optional field, so what is the difference between two?
if i try something like this, this also works
class POST(BaseModel):
title: str
content: str
published: bool = True
rating: int = None
rating: int = None is not correct. It is a mistake but python simply ignores static typing so here is no difference in behaviour.
For example in Java you will get NullPointerException.
Try to use mypy for typing checks (mypy post_model.py)
Optional case will be completed without errors:
Success: no issues found in 1 source file
However non Optional case will cause error:
post_model.py:7: error: Incompatible types in assignment (expression has type "None", variable has type "int")
Found 1 error in 1 file (checked 1 source file)
I dont think there is any difference except for the fact that by using Optional Key word we explicitly telling that this parameter Is optional both in code and swagger.
Note that this is not the same concept as an optional argument, which is one that has a default. An optional argument with a default does not require the Optional qualifier on its type annotation just because it is optional. For example:
def foo(arg: int = 0) -> None:
...
On the other hand, if an explicit value of None is allowed, the use of Optional is appropriate, whether the argument is optional or not. For example:
def foo(arg: Optional[int] = None) -> None:
...