I keep getting an error that says
AttributeError: 'NoneType' object has no attribute 'something'
The code I have is too long to post here. What general scenarios would cause this AttributeError
, what is NoneType
supposed to mean and how can I narrow down what's going on?
print
functions (or statements depending on the version) to reveal the actual values that variables actually have in the code that's having this problem.
yourobject = somthing_that_is_None
before calling yourobject.babyruth
. Maybe something_that_is_None
is a function that return None
. Without the code is impossible to know.
None
.
NoneType means that instead of an instance of whatever Class or Object you think you're working with, you've 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 you're 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'
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 don't 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 you've just assigned None
to mylist
. If you next try to do, say, mylist.append(1)
Python will give you this error.
The NoneType
is the type of the value None
. In this case, the variable lifetime
has a value of None
.
A common way to have this happen is to call a function missing a return
.
There are an infinite number of other ways to set a variable to None, however.
lifetime
had a value of None
(pre-edit). He was trying to access the lifetime attribute of something else that was None
.
Consider the code below.
def return_something(someint):
if someint > 5:
return someint
y = return_something(2)
y.real()
This is going to give you the error
AttributeError: 'NoneType' object has no attribute 'real'
So points are as below.
In the code, a function or class method is not returning anything or returning the None Then you try to access an attribute of that returned object(which is None), causing the error message.
It means the object you are trying to access None
. None
is a Null
variable in python. This type of error is occure de to your code is something like this.
x1 = None
print(x1.something)
#or
x1 = None
x1.someother = "Hellow world"
#or
x1 = None
x1.some_func()
# you can avoid some of these error by adding this kind of check
if(x1 is not None):
... Do something here
else:
print("X1 variable is Null or None")
When building a estimator (sklearn), if you forget to return self in the fit function, you get the same error.
class ImputeLags(BaseEstimator, TransformerMixin):
def __init__(self, columns):
self.columns = columns
def fit(self, x, y=None):
""" do something """
def transfrom(self, x):
return x
AttributeError: 'NoneType' object has no attribute 'transform'?
Adding return self
to the fit function fixes the error.
return
anything will implicitly return None
. This is also the case if your function is basically if something: return value
which will then end up in the implicit return None
limbo when something
is not truthy. (The answer by PHINCY L PIOUS elaborates on this particular case.)
if val is not None:
print(val)
else:
# no need for else: really if it doesn't contain anything useful
pass
Check whether particular data is not empty or null.
g.d.d.c. is right, but adding a very frequent example:
You might call this function in a recursive form. In that case, you might end up at null pointer or NoneType
. In that case, you can get this error. So before accessing an attribute of that parameter check if it's not NoneType
.
if foo is not None:
You can get this error with you have commented out HTML in a Flask application. Here the value for qual.date_expiry is None:
<!-- <td>{{ qual.date_expiry.date() }}</td> -->
Delete the line or fix it up:
<td>{% if qual.date_attained != None %} {{ qual.date_attained.date() }} {% endif %} </td>
None of the other answers above gave me the correct solution. I had this scenario:
def my_method():
if condition == 'whatever':
....
return o
else:
return None
answer = mymethod()
if answer == None:
print('Empty')
else:
print('Not empty')
Which errorred with:
File "/usr/local/lib/python3.9/site-packages/gitlab/base.py", line 105, in __eq__
if self.get_id() and other.get_id():
AttributeError: 'NoneType' object has no attribute 'get_id'
In this case you can't do equality for None. To fix it I changed it to:
if answer is None:
print('Empty')
else:
print('Not empty')
Success story sharing
None
out of something. An explicitfoo = None
is unlikely to be the problem; it's going to befoo = something()
and you don't realizesomething()
might returnNone
when it doesn't succeed or the result set was empty or whatever.