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[Solved] ValueError when checking if variable is None or numpy.array

Hello Guys, How are you all? Hope You all Are Fine. Today I get the following error ValueError when checking if variable is None or numpy.arrayv in python. So Here I am Explain to you all the possible solutions here.

Without wasting your time, Let’s start This Article to Solve This Error.

How ValueError when checking if variable is None or numpy.array Error Occurs?

Today I get the following error ValueError when checking if variable is None or numpy.arrayv in python.

How To Solve ValueError when checking if variable is None or numpy.array Error ?

  1. How To Solve ValueError when checking if variable is None or numpy.array Error ?

    To Solve ValueError when checking if variable is None or numpy.array Error On the other side of things, if you want to test whether an object is a NumPy array, you can test its type:

  2. ValueError when checking if variable is None or numpy.array

    To Solve ValueError when checking if variable is None or numpy.array Error On the other side of things, if you want to test whether an object is a NumPy array, you can test its type:

Solution 1

Using not a to test whether a is None assumes that the other possible values of a have a truth value of True. However, most NumPy arrays don’t have a truth value at all, and not cannot be applied to them.

If you want to test whether an object is None, the most general, reliable way is to literally use an is check against None:

if a is None:
    ...
else:
    ...

This doesn’t depend on objects having a truth value, so it works with NumPy arrays.

Note that the test has to be is, not ==is is an object identity test. == is whatever the arguments say it is, and NumPy arrays say it’s a broadcasted elementwise equality comparison, producing a boolean array:

>>> a = numpy.arange(5)
>>> a == None
array([False, False, False, False, False])
>>> if a == None:
...     pass
...
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: The truth value of an array with more than one element is ambiguous.
 Use a.any() or a.all()

On the other side of things, if you want to test whether an object is a NumPy array, you can test its type:

# Careful - the type is np.ndarray, not np.array. np.array is a factory function.
if type(a) is np.ndarray:
    ...
else:
    ...

You can also use isinstance, which will also return True for subclasses of that type (if that is what you want). Considering how terrible and incompatible np.matrix is, you may not actually want this:

# Again, ndarray, not array, because array is a factory function.
if isinstance(a, np.ndarray):
    ...
else:
    ...    

Solution 2

To stick to == without consideration of the other type, the following is also possible.
type(a) == type(None)

Summery

It’s all About this issue. Hope all solution helped you a lot. Comment below Your thoughts and your queries. Also, Comment below which solution worked for you? Thank You.

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