How do I fix the Python nameerror name true is not defined error message?
Well, this article got your back. Just simply keep on reading.
In this article, we’ll show you how you’re going to resolve the nameerror: name ‘true’ is not defined error.
What is “nameerror: name ‘true’ is not defined”?
The error message nameerror name true is not defined raised because you have a typo or a misspelled variable name “True.”
For example:
sample_var = true👎
if sample_var == True:
print("sample_var is true")
else:
print("sample_var is false")If you run this code, it will throw a name error that indicates the name true is not defined.
The error message occurs because you are using “True” in a small letter (true). True should be capitalized.
There are instances when “True” is being used in a context though it is not defined. In Python, “True” is a built-in constant that represents the boolean value of true.
Moreover, if you don’t know, Python is case-sensitive, which means that ‘True’ and ‘true’ are not the same.
If you misspell a variable or function name, Python will not be able to find it, that results to this error.
How to fix “nameerror name true is not defined”?
To fix the nameerror: name ‘true’ is not defined error message in Python, ensure that “True” is capitalized.
Solution 1: Use correct boolean value
You have to check if you are using the correct boolean value. Kindly refer to the illustration below.]
Incorrect code:
❌ sample_var = trueCorrect code:
✅ sample_var = TrueHere’s the complete code:
✅ sample_var = True
if sample_var == True:
print("sample_var is true")
else:
print("sample_var is false")
As you can see, we just capitalize “True” and it resolves the issue. If you are using “true,” you just have to change it to “True.”
Output:
sample_var is true
Solution 2: Use 1 instead
You can also use 1 instead of using True: In Python, the boolean value of true can also be represented by the integer 1.
For example:
sample_var = True
if sample_var == 1:✅
print("sample is true")
else:
print("sample is false")
Output:
Sample is trueSolution 3: Define true as a variable
If you want to use the lowercase version of true, you can define it as a variable and assign it the value of True.
For example:
✅ true = True
if true:
print("This sample is true")Output:
This sample is trueConclusion
The error message nameerror name true is not defined raised because you have a typo or a misspelled variable name “True.”
This article explores what this error is all about and already provides solutions to help you fix this error.
You could also check out other “nameerror” articles that may help you in the future if you encounter them.
- Nameerror name keras is not defined
- Nameerror: name sns is not defined
- Nameerror name ‘json’ is not defined
We are hoping that this article helps you fix the error. Thank you for reading itsourcecoders 😊
Frequently Asked Questions
What is Python NameError and what causes it?
NameError is raised when Python encounters a name (variable, function, class) that hasn’t been defined in the current scope. Most common causes: typo in variable name, using a variable before assigning it, missing import, or referencing a variable that was defined inside a function but accessed outside it.
How do I fix ‘name X is not defined’?
Check three things: (1) Is the name a typo? Compare with the spelling where you defined it. (2) Did you import it? Add ‘from module import X’ or ‘import module’ at the top. (3) Is X defined in a different scope (inside a function, conditional branch, or with-block) that hasn’t executed yet at the point you’re using it? Move the definition before the use.
Why does my variable work in one cell but not another (Jupyter)?
Jupyter kernels keep state between cells. If you defined X in cell 5 and run cell 3 later, X exists. But after Kernel-Restart, only the cells you re-run define their variables. Always run cells top-to-bottom on a fresh kernel before submitting. Use ‘Restart and Run All’ to verify your notebook is reproducible.
What is the difference between NameError and AttributeError?
NameError: the name itself doesn’t exist anywhere in scope (typo, missing import, scope issue). AttributeError: the name exists and points to an object, but that object has no such attribute/method (typo on method name, wrong object type). NameError is about the variable; AttributeError is about what’s inside it.
Where can I find more NameError fixes?
Browse the NameError reference hub for 49+ specific fixes (NumPy, pandas, Jupyter, Python 2 to 3 migration). For Python scope rules see the Python Tutorial hub. For attribute-level errors see AttributeError.
Caren Bautista
Technical Writer at PIES IT Solution
Responsible for crafting clear, well-structured, and beginner-friendly content across the platform. Handles the writing, proofreading, and editorial review of tutorials, guides, and documentation to ensure every article is accurate, readable, and easy to follow.
Expertise: Technical Writing · Content Creation · Documentation · Editorial Writing · JavaScript · TypeScript · Python · Python Errors · HTTP Errors · MS Excel · View all posts by Caren Bautista →