Today, we’ll walk you through how to fix the Python nameerror: name ‘_c’ is not defined error.
We understand that sometimes there is an error that needs assistance to resolve it.
Fortunately, this article is here to help you to fix this error.
What is “nameerror name ‘_c’ is not defined”?
The error message nameerror: name ‘_c’ is not defined occurs when you are working with pytorch in jupyter notebook.
In addition to that, it also happens if you’re trying to use a variable “_c,” but that variable or function has not been defined in the current scope.
This error message indicates that the Python interpreter cannot find a definition for the variable or function that is being referenced in the code.
Why does this error occur?
This error message occurs due to some reasons, which include the following:
❌ When you forgot to define it before using it.
❌ Misspelled the name of a variable or function.
❌ If you try to access a variable or function outside of its scope.
❌ If you’re using a module or package in your Python program and forgot to import it.
How to fix “nameerror: name ‘_c’ is not defined”?
To fix this error message, you just have to install Cython in order for pytorch to work.
Here’s the following command to install Cython:
✅ pip3 install CythonTake note: PyCharm support Cython whereas the Jupyter environment does not.
In some cases, restarting the kernel will help to resolve the error.
To check Cython version here is the following code:
✅ import torch
print(torch.__version__)If you encounter this error while importing torch, you just have to execute the following:
You have to change the directory before calling import torch.
1. cd test dir ✅
2. python ✅ After that, add the import torch at the top or beginning of your code.
✅ import torchConclusion
The error message nameerror: name ‘_c’ is not defined occurs when you are working with pytorch in jupyter notebook.
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 true is not defined
- Nameerror name keras is not defined
- Nameerror: name sns 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 →