22 points
Python:
return a or b
i like it because it reads like a sentence so it somewhat makes sense
and you can make it more comprehensive if you want to:
return a if a is not None else b
14 points
*
7 points
I personally dislike this because when you read “or” you expect some boolean result not a random object :/
4 points
1 point
For newer python people, they see return a or b and typically think it returns a boolean if either is True. Nope. Returns a if a is truthy and then checks if b is truthy. If neither are truthy, it returns b.
7 points
*
Returns a if a is truthy and then checks if b is truthy. If neither are truthy, it returns b.
Not quite. If a is not truthy, then the expression a or b will always return b.
So, there is never any reason to check the truthiness of b.
you can paste this in your repl to confirm it does not.
class C:
def __repr__(self): return [k for k, v in globals().items() if v is self][0]
def __bool__(self):
print(f"{self}.__bool__() was called")
return False
a, b = C(), C()
print(f"result: {a or b}")
output
a.__bool__() was called
result: b
3 points
