Error Handling in Python

Errors are a natural part of programming. Whether it's a typo, a missing file, or unexpected user input, errors can cause your program to crash if not handled properly. In Python, error handling is a powerful feature that helps developers anticipate, catch, and resolve issues gracefully. This not only improves the user experience but also ensures your code runs more reliably.

Types of Errors in Python

Before diving into error handling, it's important to understand the two main types of errors:

Syntax Errors: These occur when the code structure is incorrect. For example:

python

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if x > 5

    print("Hello")

Missing a colon results in a syntax error.

Runtime Errors (Exceptions): These occur during execution, such as dividing by zero or accessing an undefined variable:

python

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print(10 / 0)  # ZeroDivisionError

The Try-Except Block

Python uses the try-except block to handle exceptions. Here’s the basic syntax:

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try:

    # code that might raise an error

    result = 10 / 0

except ZeroDivisionError:

    print("You can't divide by zero!")

If an error occurs in the try block, Python jumps to the except block and executes it.

Catching Multiple Exceptions

You can handle different types of exceptions using multiple except blocks:

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try:

    value = int("abc")

except ValueError:

    print("Invalid input: not a number.")

except Exception as e:

    print("An unexpected error occurred:", e)

Using Exception allows you to catch any error that wasn’t specifically handled earlier.

The Else and Finally Blocks

else runs if no exception occurs:

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try:

    print("All good!")

except:

    print("Something went wrong.")

else:

    print("No errors occurred.")

finally always runs, whether an error occurs or not:

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try:

    x = 5

finally:

    print("Cleaning up resources.")

Raising Custom Exceptions

You can also raise your own exceptions using the raise keyword:

python

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def divide(x, y):

    if y == 0:

        raise ValueError("Cannot divide by zero.")

    return x / y

Final Thoughts

Error handling in Python is essential for building robust applications. By using try-except, along with else, finally, and custom exceptions, you can make your code more reliable and user-friendly. Start with simple error catching and gradually expand your knowledge to write smarter and safer programs.

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