Programming often involves dealing with errors and exceptions. Understanding different types of errors and how to handle them is vital in writing robust, error-free Python code.
Types of Errors
There are numerous types of errors in Python, but here are a few common ones:- SyntaxError: These errors occur when the parser detects an incorrect statement.
print(Hello World) # Missing quotation marks. Causes a SyntaxError.
TypeError: This error occurs when an operation or function is applied to an object of an inappropriate type.
'2' + 2 # Can't add a string to an integer. Causes a TypeError.
ValueError: Raised when a built-in operation or function receives an argument that has the right type but an inappropriate value.
int('Python') # Can't convert 'Python' to an integer. Causes a ValueError.
Exception Handling
Python uses try-except blocks to handle exceptions. Here’s a simple example:
try:
num = int(input("Enter a number: "))
except ValueError:
print("That's not a valid number!")
You can also include else and finally:- else: If there is no exception, then the else statement will be executed.
- **
finally**: This block of code will be executed no matter if there’s an exception or not.
try:
num = int(input("Enter a number: "))
except ValueError:
print("That's not a valid number!")
else:
print("I'm in the else block!")
finally:
print("Execution finished.")
Exercise
Your objective now is to create Python software that prompts the user for an integer and returns the square of that number. If the user enters a non-integer value, use a try-except block to catch a **‘ValueError’ **exception.
Conclusion
Errors and exceptions are common in any program, but learning how to handle them will improve the reliability and robustness of your Python scripts. Always remember that it is preferable to anticipate and resolve mistakes rather than have your application crash!