Common Python Errors and How to Fix Them
Browse all documented Python errors with detailed explanations, root causes, and step-by-step fixes.
TemplateNotFound: 'base.html' template not found in the templates directory
This error occurs when a templating engine, such as Jinja2, is unable to locate a template file.…
NameError: name 'total' is not defined
This error occurs when you try to use a variable that has not been assigned a value yet or has not been defined in the c…
TemplateNotFound: Unable to find template 'user_profile.html' in the templates d
This error occurs when a template engine in a Python web framework, such as Flask or Django, is unable to locate a speci…
SyntaxError: invalid syntax, possibly a bit shift, not in operator or comma
This error occurs when Python encounters syntax that it does not understand or expects a different type of syntax, such …
TemplateNotFound: templates/layout.html
This error occurs when the Jinja2 template engine in Flask or Django is unable to find a template file that is reference…
RuntimeError: Cannot access a closed file
This error occurs when you try to access a file that has been closed, likely due to a file descriptor leak.…
CursorError: Database connection already closed when trying to execute query.
This error occurs when you try to execute a SQL query on a database cursor that has already been closed. Typically, this…
CursorError: No rows in result set
This error occurs when trying to fetch rows from a database cursor, but there are no rows to fetch. It typically happens…
Can't pickle local object '_thread._Local' of type '_thread._Local': attribute l
This error occurs when Python is unable to serialize an object due to its internal state or attributes, usually because …
invalid syntax (<string>, line 3) SyntaxError: invalid syntax
This error occurs when Python encounters a line of code that it cannot parse, usually due to a misplaced or missing char…
Flask app not found: 'my_app' (make sure to run 'flask run' in the correct direc
This error occurs when Flask is unable to find the application instance that was registered with the current Flask app c…
TemplateNotFound: Could not locate template 'base.html' in the templates directo
This error occurs when Flask or another Python web framework cannot find a specified template file. It's usually due to …
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