LookupError — Expert Playground
Base class for lookup errors (KeyError, IndexError)
Python Playground
# Exception groups (Python 3.11+)
import sys
print(f"Python {sys.version}")
# Exception hierarchy inspection
print(f"LookupError MRO:")
for cls in LookupError.__mro__:
print(f" {cls.__name__}")
# Exception attributes
try:
raise LookupError("lookup failed")
except LookupError as e:
print(f"\nException attributes:")
print(f" args: {e.args}")
print(f" __traceback__: {type(e.__traceback__)}")
# Traceback manipulation
import traceback
tb_lines = traceback.format_exception(type(e), e, e.__traceback__)
print(f" Traceback lines: {len(tb_lines)}")
Output
Click "Run" to execute your code
Understanding the exception hierarchy and traceback system helps build robust error handling and debugging tools.
Challenge
Try modifying the code above to explore different behaviors. Can you extend the example to handle a new use case?