python – Why do I get AttributeError: NoneType object has no attribute something?

python – Why do I get AttributeError: NoneType object has no attribute something?

NoneType means that instead of an instance of whatever Class or Object you think youre working with, youve actually got None. That usually means that an assignment or function call up above failed or returned an unexpected result.

You have a variable that is equal to None and youre attempting to access an attribute of it called something.

foo = None
foo.something = 1

or

foo = None
print(foo.something)

Both will yield an AttributeError: NoneType

python – Why do I get AttributeError: NoneType object has no attribute something?

Others have explained what NoneType is and a common way of ending up with it (i.e., failure to return a value from a function).

Another common reason you have None where you dont expect it is assignment of an in-place operation on a mutable object. For example:

mylist = mylist.sort()

The sort() method of a list sorts the list in-place, that is, mylist is modified. But the actual return value of the method is None and not the list sorted. So youve just assigned None to mylist. If you next try to do, say, mylist.append(1) Python will give you this error.