Try Except Strategies for Python Beginners – Making Debugging Easy with Exception Handling!

Try Except Strategies for Python Beginners – Making Debugging Easy with Exception Handling!

If you're just starting to learn Python, you might feel confused when you first encounter the try except statement. You might wonder, "What class name should I memorize?" or "When should I use this?" In this post, I will explain the core concepts of Python exception handling and provide a step-by-step strategy for beginners to use try except.

Why is Python Exception Handling Important?

When running your code, things don't always work as expected. Users might input incorrect values, files might be missing, or the network might disconnect... If the program crashes in such scenarios, it results in a poor user experience.

That's where Python's exception handling (try except) comes in handy.

The purpose of exception handling is simple: to keep the program running safely even when errors occur.

What Does a Try Except Look Like?

try:
    # Code that may cause an error
except ExceptionClass as e:
    # What to do when an error occurs

For example:

try:
    result = 10 / 0
except ZeroDivisionError as e:
    print("Cannot divide by 0:", e)

The key here is the ZeroDivisionError, which is a type of exception class. This class acts as a 'label' that indicates what kind of error has occurred.

What is an Exception Class and Do I Need to Memorize It?

Many Python beginners ask this question:

"Do I need to memorize all these exception classes?"

The answer is no!

Even professional developers do not memorize every exception class. Instead, they become familiar with a few common exceptions and refer to the error messages when issues arise.

For instance:

FileNotFoundError: [Errno 2] No such file or directory: 'none.txt'

In that case, you would write:

except FileNotFoundError:

That's how you use it.

Top 7 Common Python Exception Classes

Learning just these will help you handle most Python exception handling situations.

Become Familiar with Try Except as a Beginner!

1. Wrap it with Exception if you're unsure.

try:
    dangerous_code()
except Exception as e:
    print("An error occurred:", e)

1. Refine the specific exception class by observing the error message.

2. Trust the auto-completion of your IDE (code editor). Most of them provide recommendations.

3. Repeatedly encountering the same problem will enhance your understanding naturally.

Exception Handling is Your Friend for Debugging

Python exception handling is not just a tool for avoiding errors; it's a powerful debugging tool for tracking errors and identifying causes.

Exception messages usually appear like this:

Traceback (most recent call last):
  File "main.py", line 2, in <module>
    x = 10 / 0
ZeroDivisionError: division by zero

This provides the filename, line number, and type of error, enabling you to pinpoint issues accurately. Thus, using exception handling well can make debugging easier.

Additional Exception Class – StopIteration

StopIteration is the exception that is raised when an iterator has no more items to return. In a typical for loop, it is handled automatically, so you usually don't need to worry, but when using the next() function, you often have to handle it manually.

Example:

it = iter([1, 2])
print(next(it))  # 1
print(next(it))  # 2
print(next(it))  # StopIteration occurs

Or in the following code:

try:
    category = next(cat for cat in all_categories if cat.slug == category_slug)
except StopIteration:
    pass  # Do nothing

Here, it is used to pass without doing anything if there is no category with that slug. It's the minimal defense to avoid halting the code flow.

Conclusion – Python Exception Handling May Seem Tough at First, But You Get Used to It Quickly

There's no need to memorize all exception classes or achieve perfect exception handling from the start. Instead, develop the habit of recognizing problem situations, wrapping with try except, and analyzing error messages.

Python exception handling strengthens your programs and makes it easier to identify issues later. For beginners, having survivability in real situations is more important than perfection. Try except will be your first step towards that.

In the next post, I will explain the extended exception handling flow with try except else finally structure! 😊