How do I check if a variable is None in Python?

Testing for NoneType in Python

When working with methods that may return NoneType values, it becomes necessary to ascertain whether a variable holds such a value. To accomplish this, Python provides the is operator.

Using the is Operator

To test if a variable is NoneType, use the following syntax:

<code class="python">if variable is None:</code>

Explanation

None is the sole singleton object of NoneType in Python. Using the is operator, you can determine if a variable is identical to None.

Alternative Approaches

While the is operator is recommended by the Python Coding Style Guidelines, alternatives exist:

• Equality Operators (==, !=): While not recommended for testing None, these operators can be used in limited situations where object identity comparisons are unimportant.
• Not Equal To (not): This operator can be useful in negations, e.g., if variable is not None.

Best Practice

For the most consistent and idiomatic code, adhere to Python's Coding Style Guidelines and use the is operator when testing for NoneType.

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