Python Programming with Jupyter and Anaconda

Debugging and Error Handling in Python

Debugging is the process of identifying and fixing errors in your code. If you've ever encountered an error while running your code, you know how frustrating it can be. In this lesson, you'll learn how to debug and handle errors in Python, including using try/except statements.

Types of Errors

There are three main types of errors in Python: syntax errors, runtime errors, and logical errors. Syntax errors occur when you have a typo or other mistake in your code that prevents it from running at all. Runtime errors occur when your code runs into a problem while executing, such as trying to divide by zero. Logical errors occur when your code runs without errors, but produces the wrong result.

Debugging Techniques

When you encounter an error in your code, the first step is to read the error message carefully. The error message will often tell you exactly what went wrong and where. You can also use print statements to help you identify where the error occurred and what the value of certain variables is at that point in the code.

Another useful debugging technique is to use a debugger. A debugger is a tool that allows you to step through your code line by line and see the values of variables at each step. You can also set breakpoints, which pause the execution of your code at a certain point so you can inspect the variables and state of the program.

Error Handling

In addition to debugging techniques, you can also handle errors in your code using try/except statements. A try/except block allows you to catch errors and handle them gracefully, without crashing your program. Here's an example:

try:
    num = int(input('Enter a number: '))
    print(10/num)
except ValueError:
    print('Invalid input')
except ZeroDivisionError:
    print('Cannot divide by zero')

In this example, we're trying to divide the number 10 by the number entered by the user. If the user enters an invalid input (such as a string instead of a number), a ValueError will be raised. If the user enters zero, a ZeroDivisionError will be raised. We catch these errors using except blocks and print an appropriate error message.

Debugging and Error Handling in Python