In the programming world, things don’t always go as planned. There might be situations when a certain part of the code fails due to various reasons, leading to disruptions or undesired behaviors. These disruptions are broadly classified as errors and exceptions.
Errors in programming can be generally categorized into three types:
if 5 > 2: print("Five is greater than two!")
This will raise a syntax error due to incorrect indentation.
def add(a, b): return a - b print(add(5, 3)) # This will print 2 instead of 8.
print(1/0) # This raises a ZeroDivisionError.
Exceptions are runtime errors that can potentially be handled by the code, allowing the program to continue its execution or gracefully signal the problem to the user.
Standard exceptions in Python are built into the core language, but one can also define custom exceptions for specific error handling scenarios.
Some common built-in exceptions are:
IndexError: Raised when accessing an index that doesn’t exist in a list.
TypeError: Occurs when an operation is performed on an inappropriate data type.
ValueError: Raised when a function receives an argument of correct type but inappropriate value.
lst = [1, 2, 3] print(lst) # This raises an IndexError.
Python provides a mechanism to handle exceptions using a combination of
tryblock: Code that might raise an exception is placed here.
exceptblock: Here, we write code to handle the exception.
elseblock: If there’s no exception, this block is executed.
finallyblock: This block is always executed, irrespective of an exception being raised or not.
try: result = 10 / 0 except ZeroDivisionError: print("Can't divide by zero!") else: print("Division successful!") finally: print("Exiting the program.")
Understanding the nature and types of errors and exceptions is crucial in writing robust Python programs. Proper exception handling ensures that your program can deal with unforeseen circumstances in a graceful manner, enhancing the user experience and preventing potential data loss or corruption.