Explain
Tracebacks (how to read the scary wall of text)
A traceback is Python showing you exactly where it got confused. You don’t need to “understand all of it”. You need three parts.
TL;DR (read from the bottom)
- The last line is the error type + message.
- The line above it usually points at the code that triggered it.
- Fix one thing, rerun, repeat.
Common beginner errors (and what they mean)
IndentationError
Python uses indentation as syntax. Mixed spaces/tabs or missing indents.
Looks like
IndentationError: expected an indented blockKeyError
You asked a dict for a key that doesn’t exist.
Looks like
KeyError: 'info'TypeError
You used the wrong type (like treating a list as a dict).
Looks like
TypeError: list indices must be integers or slices, not strFileNotFoundError
Usually: you ran the program from the wrong folder.
Looks like
FileNotFoundError: [Errno 2] No such file or directoryThe “ask for one fact” trick
When you’re stuck, print the smallest fact that tells you what you have: type, length, keys.
High-signal prints
print(type(x))
print(len(x))
print(list(x.keys())[:10])