Error Handling

In Python, errors and exceptions can occur when a program encounters unexpected situations or errors in the code. These errors can lead to the program crashing or producing incorrect results. Error handling helps us handle these situations gracefully and prevent our program from crashing.

Try-Except Block

One way to handle errors and exceptions in Python is to use the try-except block. The try block contains the code that might raise an exception, and the except block handles the exception if it occurs.

Here's an example of using the try-except block to handle errors:

1# Define a function that divides two numbers
2
3def divide_numbers(a, b):
4    try:
5        result = a / b
6        print(f'The result of the division is: {result}')
7    except ZeroDivisionError:
8        print('Error: Cannot divide by zero!')
9    except TypeError:
10        print('Error: Invalid data types!')
11    except:
12        print('An unexpected error occurred!')
13
14# Call the function
15
16divide_numbers(10, 2)
17divide_numbers(10, 0)
18divide_numbers('10', 2)
19divide_numbers(10, '2')
20divide_numbers(5, 2)

In the example above, the function divide_numbers() divides two numbers. The try block attempts to perform the division and print the result. If a ZeroDivisionError occurs, it prints an error message indicating that division by zero is not allowed. If a TypeError occurs, it prints an error message indicating that the data types of the input are invalid. Finally, if any other unexpected error occurs, it prints a generic error message.

Using the try-except block allows us to anticipate and handle specific types of errors gracefully. It prevents our program from crashing and allows us to handle different types of errors differently.

Exception Hierarchy

In Python, exceptions are organized in a hierarchical structure. The base class for all exceptions is the BaseException class. Some commonly used exception classes include:

• Exception: Represents the base class for all built-in exceptions.
• ZeroDivisionError: Raised when a division or modulo operation is performed with zero as the divisor.
• TypeError: Raised when an operation or function is applied to an object of inappropriate type.

We can catch specific types of exceptions by specifying the exception class in the except statement. We can also catch multiple types of exceptions by specifying them in a comma-separated list.

Conclusion

Handling errors and exceptions in Python is essential for writing robust and reliable code. By using the try-except block, we can handle specific types of exceptions and prevent our program from crashing. It is important to anticipate the potential types of errors that can occur and handle them gracefully. By doing so, we can create more resilient and user-friendly applications.

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# Define a function that divides two numbers

​

def divide_numbers(a, b):

    try:

        result = a / b

        print(f'The result of the division is: {result}')

    except ZeroDivisionError:

        print('Error: Cannot divide by zero!')

    except TypeError:

        print('Error: Invalid data types!')

    except:

        print('An unexpected error occurred!')

​

# Call the function

​

divide_numbers(10, 2)

divide_numbers(10, 0)

divide_numbers('10', 2)

divide_numbers(10, '2')

divide_numbers(5, 2)