Fix Python NameError: Name 'False' Not Defined

Python is a powerful programming language. But errors like NameError can confuse beginners. One such error is NameError: Name 'False' Not Defined.

This error occurs when Python cannot find the name False in the current scope. Let's explore why this happens and how to fix it.

What Causes NameError: Name 'False' Not Defined?

The error usually occurs when False is misspelled or not recognized. In Python, False is a built-in boolean value. It should always be written with a capital 'F'.

If you write false instead of False, Python will raise a NameError. This is because false is not a defined keyword in Python.

Example of the Error

Here is an example that triggers the error:

# Incorrect usage of 'false'
if false:
    print("This will not work.")

When you run this code, you will see the following error:

NameError: name 'false' is not defined

How to Fix the Error

To fix this error, ensure you use the correct spelling of False. Here is the corrected code:

# Correct usage of 'False'
if False:
    print("This will not print.")
else:
    print("This will print.")

When you run this code, the output will be:

This will print.

Common Scenarios Where This Error Occurs

This error can also occur in other scenarios. For example, when working with functions or classes. If you mistakenly use false instead of False, the error will appear.

For more on handling errors in functions and classes, check out Python NameError in Functions and Classes.

Preventing NameError in Python

To avoid NameError, always double-check your variable names and keywords. Use Python's built-in functions and keywords correctly.

For more tips, read How to Fix NameError in Python.

Conclusion

The NameError: Name 'False' Not Defined is a common mistake. It happens when False is misspelled or not recognized. Always use the correct spelling and capitalization.

For more on Python errors, visit Understanding NameError in Python.