Why is the Boolean value of [None] True and the Boolean value of [] False?
Question:
I was working on a project and stumbled across this weird anomaly, apparently the Boolean value for any list or tuple with an None value is True
Input
print(bool([])) # empty list
print(bool(())) # empty tuple
print(bool([None])) # list with None
print(bool((None,))) # tuple with None
Output
False
False
True
True
can someone give a brief explanation as to why an list/tuple object with presumably None(null) value will have a Boolean value of True instead of False?
Answers:
A tuple or a list evaluate to False in a boolean context if they’re empty. (None,) and [None] are a tuple/list with 1 element (the element None), hence not empty… therefore they evaluate to True in a boolean context
I was working on a project and stumbled across this weird anomaly, apparently the Boolean value for any list or tuple with an None value is True
Input
print(bool([])) # empty list
print(bool(())) # empty tuple
print(bool([None])) # list with None
print(bool((None,))) # tuple with None
Output
False
False
True
True
can someone give a brief explanation as to why an list/tuple object with presumably None(null) value will have a Boolean value of True instead of False?
A tuple or a list evaluate to False in a boolean context if they’re empty. (None,) and [None] are a tuple/list with 1 element (the element None), hence not empty… therefore they evaluate to True in a boolean context