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- 1 To know about Python AssertionError! Complete Guide
To know about Python AssertionError! Complete Guide
Would you like to understand everything about exceptions in Python? You are at the right place to learn, because today we have to share knowledge on Python AssertionError with different examples to clarify its fundamental idea.
Different steps are mentioned in detail also with the author’s recommendations for beginners. Must read it from start to end if you want to cover the AssertionError topic in Python.
I know your situation! Don’t worry
You are searching on the Internet to get a solution for the AssertionError exception that was raised in your Python code. You do not need to worry, because I have published this post for you guys to share my experience as well as knowledge that I have. Everything with proper examples shared with you, I didn’t want to hide anything from you.
I recommend you to read this article which is full of information related to Python AssertionError which is the famous exception that arose while working on your project, mostly it raised due to the failure of an assert statement.
Why do you get this error, you know?
You have used an assert statement in your code and got an AssertionError Exception. I want to share your case here, your concept will be clear
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assert any_condition_or_expression, "Optional Value" |
assert function takes two parameters, one is a condition or expression and another is an optional value that shows when the condition is false. When the first parameter that is the condition is true, you will not get any error, if this condition becomes false you will get an assertion error and an optional value will return.
You need to analyze your code where you are making errors, just share it with me in case you are unable to find an error, and I will help you, don’t worry!
What is an assertion error in the facet of Python language?
AssertionError is raised when a condition is false with an assert statement. Assert statement is the special keyword used in Python language to check a condition, whether it is false or true. If this condition is true, an interpreter goes to the next statement for execution. If it return false hten it go to optional paramter to execute stamten whcih cotnain useally a user frienldy error message.
Coding Example:
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a = 10 assert a == 20, "a value is not equal to 10" print(a) |
Step-by-Step Guide for Debugging Assertions
Would like to debug assertions in your Python program, here is step by step-by-step guide for beginners to understand properly with examples. Every section is explained as well for beginners, just try to understand!
1. Enable Assertions
If you want to debug assertion error in your Python code, you should know that by default it’s enabling and disabling.
By default in your Python system assertion is enabled which means that whenever the condition is written with an assert statement and a false, an exception will raise. But when you disable assertion checking, you will not get an error. You need to enable it if it is disabled.
You need to use -O command to disable assertion if you want, your Python executing command will be like this one:
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python -O my_code.py |
When you run this command your Python file will be executed without showing an exception error,
2. Review the AssertionError Message
It is good practice to use the 2nd parameter in the assert statement, in the 2nd parameter you can give a useful message to identify the error. When it shows an assertion message in the console, you will be able to understand, what is the error about.
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assert var != 0, "It cannot divide by zero!" |
In this case, a message will show in the console saying the actual reason due to that, expectation is raising.
3. Identify the Failing Assertion
Next, you can go to your code where you used assert statements, by checking variables, expressions, their values, logic, etc you will be able to debug it easily.
4. Print Variable Values
Another good practice is to show the viable value with a print statement, which makes it easy to develop what is going on. What are the values of variables and what are expectations? Using a print statement to show the status of a variable it becomes easy to make a decision.
In this example, it shows the value of x and y in the terminal.
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x = 5 y = 0 print("x:", x) print("y:", y) |
5. Evaluate Expressions Separately
It may be the case when you have a complex expression with an assert statement, here you need to make that complex into simpler parts, and then evaluate separately. For example,
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assert expression1, "Assertion failed1" assert expression2, "Assertion failed2" assert expression3, "Assertion failed3" |
When you evaluate the different experiences separately, you may get a specific assertion message for a specific expression, which becomes easy to debug.
Author Recommendation for you
As you know that different Python exception I have discussed with you in detail with proper examples. I want to share some recommendations for you while working on Python projects and handling different assertions.
You need to use a simpler statement with an assert keyword and must write a 2nd optional parameters that show the error message in the console.
Author Recommendation in Table form
In this table, I mentioned my recommendation for my readers for better performance in code writing:
| Serial Number | Recommendation |
|---|---|
| 1 | Clarity |
| 2 | Explicitness |
| 3 | Validation |
| 4 | Readability |
| 5 | Test-Driven |
| 6 | Minimal Side Effects |
| 7 | Regular Review |
| 8 | Contextual Messages |
| 9 | Logging |
| 10 | Simplify Expressions |
| 11 | Custom Exceptions |
| 12 | Boundary Tests |
Sometimes, it doesn’t show exceptions in the console, beginners disable it, but you need to enable it while finding the actual error point in the source code. These are the basic recommendations for beginners, keep learning and enjoying Python code writing.
Conclusion
In this post, Python AssertionError is discussed with different examples and also shared best recommendations for you to do. Now it is your responsibility how you take our recommendation and share it with your friends.
If you are facing an assertion error exception, I have shared a complete step-by-step strategy to find out its root in this article. Also, a FAQ (Frequently Asked Question) section is added for understanding different questions and answers.
Can you share an error screenshort with me, may expert assist you?
FAQ
What is the alternative method to assert?
An assert statement is used to check the condition, if the condition is false an error message is shown saying that AssertionError. But the same functionality we can achieve using a decision-making structure like an if-else statement.
Have Faisal Zamir recommended best practices for the AssertionError Exception?
Yes, the author recommended some best practices to avoid assertion errors or to identify such errors. You can read this post in the section “Author Recommendation for you”.
Yes, If you have any questions related to the assert statement, you can drop your query in the comment section, and you will get an answer as soon as possible.
Additional Resource
Different resources I have shared with you as additional resources. In this section, I want to share other resources with you to learn more about Python AssertionError with proper examples. Additional resources will help you to learn more, which will make you an experienced code writer.
Here is a video lecture you can watch to learn more about assertion errors in Python with practical examples.
Feedback and Comment
AssertionError is very easy to understand and manage in the program to manage your project’s different functionalities. Instructor guide will help you to understand in a better way. At the last, you can give your beneficial comments to improve this lesson.
Our goal is to update this article in-depth to share beneficial information with users. Please share your thoughts and knowledge with me in the comments.