What Is Exceptions Handling In Python?

Introduction

We will discuss the Exceptions Handling In Python. A Python program pauses running the remaining portions of the program when it finds an error. Python errors can either be syntax errors in expressions or Python exceptions. We’ll find out whether there’s an exemption. This course will also examine the distinction between a syntax error and an exception. Then, we’ll discover how to raise exceptions, create assertions, and use trying and except blocks. The list of Python errors will then appear.

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What is an Exception?

A Python exception is a situation that arises during programme execution and prevents the normal flow of the program’s operations. Python code raises an exception when it encounters a condition that it is unable to manage. In Python, an object that explains a mistake is known as an exception.

Python programmes have two alternatives when an exception is thrown: either handle the exception right away or stop and quit.

Exceptions versus Syntax Errors

Syntax errors happen when the interpreter recognises a statement that contains an error.

Code:

Output:

Syntax errors happen when the interpreter recognises a statement that contains an error.

Code:

Output:

After running this code, we got an exception error. This type of error happens when Python code that is syntax sound runs into a problem. The name of the exception error code that was encountered was given in the output’s final line. Python gives more details about the type of exception error that occurs rather than just saying “exception error.” In this case, there was a NameError. There are numerous built-in exceptions in Python. Python does, however, provide the ability to create new exceptions.

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Catching Exceptions with the Try and Except Statement

Python’s try and except code blocks are used to capture exceptions and deal with them. Code lines that potentially cause an exception are found in the try and except clauses, respectively, while code lines that manage exceptions are found in the except clause.

Code

Output:

In the example before, the code blocks that can result in an error are placed inside the try clause. An exception is raised when a value of I larger than 2 tries to access a list item beyond its length, which is not present. The if clause then steps in to catch this exception, allowing the function to continue running unchecked.

Python assertions

An assertion is a consistency test that we can turn on or off once we’re done confirming the programme.

Comparing an assertion to an if-then condition makes it easier to comprehend. When an expression is evaluated, an exception is raised if the result is false.

The assert statement, the newest term added to Python 1.5, is used to make assertions.

Assertions are frequently used to check for valid input at the beginning of a function and to check for valid output at the end of the function call.

Finally, Python keyword

Python has a finally keyword that is always employed following a try-except block. After the try code block has terminated normally or for any other reason, the finally code block is always run.

Individual Exceptions

Python also enables us to create our own custom exceptions by letting us inherit classes from the normal built-in exceptions.

This is an example of a RuntimeError. A class that derives from RuntimeError is built in this case. We can apply this to show more in-depth details after an error is found.

In the try block, we throw a user-defined exception, and the except block is where we deal with it. The variable var is used to produce a sample instance of the class EmptyError.

Conclusion

So far, We have discussed theExceptions Handling In Python, difference between syntax errors and exceptions, we talked about various approaches to raise, catch, and handle Python exceptions. To learn more about the Exception Handling in Python and The Project based on Python, join Python Training in Coimbatore.