NameError — Expert Playground
Raised when a variable name is not found in scope
Python Playground
# Exception groups (Python 3.11+)
import sys
print(f"Python {sys.version}")
# Exception hierarchy inspection
print(f"NameError MRO:")
for cls in NameError.__mro__:
print(f" {cls.__name__}")
# Exception attributes
try:
print(undefined_variable)
except NameError 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?