Nameerror: name ‘col’ is not defined
Are you dealing with the Python nameerror: name ‘col’ is not defined while working in Pyspark? If you’re struggling to fix the name ‘col’ is not defined, keep on reading! This article discusses …
Python NameError Reference: 49+ “name X is not defined” Fixes (2026)
itsourcecode.com hosts 49+ documented fixes for Python NameError messages: the error class raised when Python encounters a name (variable, function, class, or module reference) that isn’t defined in the current scope. Most NameErrors trace to missing imports (np, pd, keras), Python 2 → 3 migration leftovers (raw_input, unicode), or Jupyter-only builtins running outside a notebook (display, get_ipython). Browse the fixes below by category.
What is a Python NameError?
A NameError is raised when Python tries to use a name that hasn’t been defined yet in the local, enclosing, or global scope. The error message always names the missing identifier in quotes, for example NameError: name 'np' is not defined means you wrote np.array(...) but never did import numpy as np. NameError is a sibling of UnboundLocalError (variable defined later in function) and a subclass of Exception.
How to fix any NameError in 4 steps
Read the missing name in quotes. The error tells you exactly which identifier is undefined.
Check if you imported it. If the name is np, pd, plt, tf, nn, or any library alias, you almost certainly need an import library as alias line at the top of the file.
Check spelling and case. Python is case-sensitive. True ≠ true. List ≠ list. A typo IS a NameError.
Check the scope. A variable defined inside a function isn’t visible outside it. A name defined in a Jupyter cell that hasn’t run yet doesn’t exist. A name in another module needs to be imported, not just typed.
Featured NameError fixes by category
📊 Library imports (numpy, pandas, matplotlib, sklearn)
The most common NameError, you used a library alias but forgot the import.
name ‘np’ is not defined (numpy)
name ‘pd’ is not defined (pandas)
name ‘keras’ is not defined
name ‘model’ is not defined
name ‘spark’ is not defined (PySpark)
name ‘sqlcontext’ is not defined (PySpark SQL)
🐍 Python built-ins and stdlib
name ‘os’ is not defined
name ‘sys’ is not defined
name ‘time’ is not defined
name ‘random’ is not defined
name ‘timedelta’ is not defined (datetime)
name ‘open’ is not defined
name ‘list’ is not defined
name ‘base’ is not defined
📓 Jupyter / IPython-only names
Names that exist inside Jupyter notebooks but raise NameError when you copy the code to a regular .py script.
name ‘display’ is not defined (IPython display)
name ‘get_ipython’ is not defined
name ‘__file__’ is not defined (Jupyter / REPL)
🔁 Python 2 → 3 migration
Names that existed in Python 2 but were removed or renamed in Python 3.
name ‘raw_input’ is not defined (use input())
name ‘unicode’ is not defined (Python 3 uses str)
🔣 Scope and self-reference
name ‘self’ is not defined (method vs function)
name ‘kwargs’ is not defined
name ‘_C’ is not defined (PyTorch internal)
name ‘x_train’ is not defined (ML notebook scope)
name ‘X’ is not defined
2026 Updated Guides
Name ‘model’ is not defined: ML notebook scope issues
Name ‘spark’ is not defined: PySpark session setup
Name ‘list’ is not defined: built-in shadowing
Name ‘__file__’ is not defined: Jupyter/REPL context
Related error categories
NameError is one of 10 hubs in our Python & JavaScript error reference cluster, 980+ documented fixes total. If your error isn’t a NameError, jump to the right hub below:
TypeError Reference, 220+ Python & JS TypeError fixes
ModuleNotFoundError Reference, 198+ Python import errors
AttributeError Reference, 173+ “object has no attribute X” fixes
ValueError Reference, 100+ pandas/NumPy/sklearn fixes
ImportError Reference, 67+ “cannot import name X from Y” fixes
RuntimeError Reference, 49+ PyTorch/CUDA/async runtime errors
SyntaxError Reference, 48+ Python & JavaScript syntax errors
ReferenceError Reference, 34+ JavaScript “is not defined” fixes
HTTP Error Reference, 35+ HTTP status code fixes (4xx, 5xx)
Python Tutorial, beginner-to-intermediate Python lessons
About this NameError reference
This NameError reference has been built since 2015 by PIES Information Technology Solutions in Binalbagan, Negros Occidental, Philippines. Every post comes from a real error encountered in production code. Used by 12,000+ Python developers monthly across the Philippines, India, the United States, and beyond.
Nameerror: name ‘_c’ is not defined
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. …
Nameerror name true is not defined
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 …
Nameerror name keras is not defined
The nameerror name keras is not defined error message usually experienced when working with Python. It happens when a Python script tries to use a name that was not defined or imported. …
Nameerror: name sns is not defined
Trying to fix the Python nameerror: name sns is not defined error message… However, you are struggling to fix it? Then, keep on reading. In this article, we’ll show how …
Nameerror name ‘json’ is not defined
In this article, we’ll walk you through how to fix the nameerror name ‘json’ is not defined error message in Python. If you’re having a hard time dealing with this error, we …
[Fixed] NameError: Name Data Is Not Defined in Python
Experiencing a nameerror name data is not defined, error message while you are working with Python Pandas? Yet, you are struggling to fix this error because you’re not familiar with it? Worry …
Nameerror name requests is not defined
In this article, we will show you how to fix the Python nameerror name requests is not defined error message. If you’re new to this error message technically, you don’t any idea …
Nameerror: name image is not defined
Are you stuck with the Python nameerror: name image is not defined error message? Well, you’re lucky enough because this article will show you how to fix this error. Apart from that, …
[Fixed] NameError: Name Torch Is Not Defined in Python
Are you encountering this Python nameerror name torch is not defined error message right now? If you don’t have any idea how to troubleshoot this error, then continue reading. In this article, …
Nameerror: name ‘sys’ is not defined
Today, we will explore how to resolve Python nameerror: name ‘sys’ is not defined error message. We know that errors are inevitable because we can’t control everything. However, there are various ways …
Nameerror: name ‘datetime’ is not defined
How to fix the Python nameerror: name ‘datetime’ is not defined error message? Fortunately, this article discusses what this error means and why it occurs. By that, you’ll understand this error thoroughly …
[Fixed] NameError: Name Time Is Not Defined in Python
The nameerror: name time is not defined is a common error you might encounter when working in Python. If you’re encountering this error right now and don’t know how to resolve it? …
Frequently Asked Questions
What is the difference between NameError and UnboundLocalError?
NameError means Python looked in all reachable scopes and never found the name. UnboundLocalError means Python found the name as a local variable but you tried to use it before it was assigned. Both are about names, but UnboundLocalError happens specifically inside functions when you read a local before writing it.
I imported the module, why is the alias not defined?
You probably did import numpy but then used np.array(...). Either change the import to import numpy as np, or use the full name numpy.array(...). The alias only exists if you create it with as.
Why does "name 'display' is not defined" happen?
display() is a built-in inside Jupyter notebooks (provided by IPython), but it does not exist in regular Python scripts. To use it outside Jupyter, explicitly import: from IPython.display import display. Better yet, replace it with print() or repr() if you do not need the rich notebook output.
Why does "name 'raw_input' is not defined" happen?
You are running Python 3 code that uses raw_input() from Python 2. In Python 3, raw_input was renamed to input. Replace every raw_input(...) with input(...). The old input() from Python 2 (which evaluated input as code) is gone, Python 3's input() always returns a string.
Why does "name '__file__' is not defined" happen in Jupyter?
The __file__ attribute exists when Python imports a module from a file, it holds that file's path. Jupyter cells are not loaded from a file path, so __file__ does not exist in notebook scope. For notebooks, use os.getcwd() to get the working directory, or hardcode the path you need.
How do I prevent NameError?
(1) Use a linter (pyflakes, ruff, pylint), they catch undefined names before runtime. (2) Use an IDE with import suggestions (VS Code Python extension, PyCharm). (3) Run mypy or pyright in CI, type checkers catch most undefined-name bugs. (4) For notebooks, restart the kernel and run all cells top-to-bottom occasionally to ensure no hidden state.
How often is this NameError reference updated?
New posts are added as we hit them in real projects. Existing posts are revised when major Python versions ship changes. Last refreshed: May 2026.