How to use the Python Error Explainer
- 1. Copy the errorCopy everything from Traceback to the last line.
- 2. Paste and explainThe tool finds the error type, the file and line, and the code.
- 3. Fix itFollow the steps and compare with the example fix.
How to read a traceback
A Python traceback reads bottom up:
- The last line names the error and gives details, for example
KeyError: 'grade'. Start here. - Just above it is the file, line number and the line of code that failed.
- Lines above that show the chain of calls that led there. Your own files are what to look at; frames inside libraries are usually not where the bug is.
The explainer covers 31 of the most common errors beginners and job candidates hit: NameError, the main TypeError messages (concatenating str and int, not subscriptable, not callable, missing or extra arguments, not iterable), IndexError, KeyError, ValueError for bad numbers and unpacking, AttributeError (including on None), ModuleNotFoundError, ImportError, ZeroDivisionError, IndentationError, TabError, SyntaxError, FileNotFoundError, RecursionError, UnboundLocalError, JSON and Unicode decoding errors, and more.
Worked example
The sample is a traceback from marks.py. The explainer reports TypeError at line 3 of marks.py, shows the line print("Total: " + total), and explains that + can't join a string and an int. It suggests str(total) or, more simply, an f-string:
print(f"Total: {total}")Fixes use details from your own error. For NameError: name 'totl' is not defined it tells you to check the spelling of totl. For ModuleNotFoundError: No module named 'sklearn' it tells you the pip package is actually called scikit-learn.
The explanation is worked out from the error text in your browser. Your code is not run, uploaded or shared. If an error isn't in the list, you still get the parsed type, message and location, which is usually enough to search for an answer.
Frequently asked questions
Do I need the whole traceback?
The last line alone works. The full traceback adds the file, line number and code, which makes the help more specific.
Does it work for errors in libraries like pandas?
Yes, it explains the final error, such as KeyError for a missing DataFrame column, and points to your own file's line when it is in the traceback.
Is my code sent anywhere?
No. Matching happens in your browser.
Do I have to pay for the python error explainer?
No, it is free. Your first explanation asks for your name and WhatsApp number one time only. Then the python error explainer and all other Uncodemy tools stay open for you with no form.