Errors & debugging
Handle failures gracefully, raise helpful errors, and debug with confidence.
Catch ValueError and print friendly message in Python
Wrap an int() call in a try/except block and print a friendly message when ValueError is raised.
try:
number = int("not_a_number")
except ValueError:
print("That's not a valid number. Please enter digits only.")Handle ValueError and ZeroDivisionError in Python with try except
Learn how to catch ValueError and ZeroDivisionError in Python with a practical safe_divide function and demonstrate error handling for invalid conversions.
def safe_divide(numerator, denominator):
try:
result = numerator / denominator
except ValueError as e:
print(f"ValueError caught: {e}")
return None
except ZeroDivisionError:
print("Cannot divide by zero!")
return None
return result
# Test cases
print(safe_divide…How to Return Success or Error as a Tuple in Python (Result Type Pattern)
Use a (bool, value) tuple as a lightweight Result type to return either a successful result or a descriptive error message from a Python function.
def divide(dividend: float, divisor: float) -> tuple[bool, float | str]:
"""Return (True, result) on success, (False, error_message) on failure."""
if divisor == 0:
return False, "Error: Division by zero"
return True, dividend / divisor
if __name__ == "__main__":
# Success case
success, r…How to Validate Input and Raise TypeError in Python
Define a function that checks its argument type and raises a TypeError early with a clear message when given a non-number.
def validate_number(value):
if not isinstance(value, (int, float)):
raise TypeError(f"Expected a number, got {type(value).__name__}")
return value * 2
if __name__ == "__main__":
try:
print(validate_number(5))
print(validate_number("hello"))
except TypeError as e:
print(…Map Exception Type to HTTP Status Code in Python
Maps Python exception types to appropriate HTTP status codes using a dictionary lookup for consistent API error handling.
EXCEPTION_STATUS_MAP = {
ValueError: 400,
KeyError: 400,
TypeError: 400,
PermissionError: 403,
FileNotFoundError: 404,
AttributeError: 404,
TimeoutError: 408,
NotImplementedError: 501,
ConnectionError: 503,
}
def status_code_for(exception_type):
try:
return EXCEPTION_S…Browse by section
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Errors & debugging — Python code examples
What you will find here
This page collects errors & debugging snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
Samples vs tutorials and challenges
Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.