This article is about Python Exception HANDLING and its error.Before going deep into this topic,let’s first know what exactly python is.
Python is an interpreted, object-oriented, high-level, dynamically semantic programming language. It is particularly desirable for Rapid Application Development as well as for usage as a scripting or glue language to tie existing components together due to its high-level built-in data structures, dynamic typing, and dynamic binding. Python’s straightforward syntax prioritises readability and makes it simple to learn, which lowers the cost of programme maintenance. Python’s support for modules and packages promotes the modularity and reuse of code in programmes. For all popular platforms, the Python interpreter and the comprehensive standard library are freely distributable and available in source or binary form.
Python Exception Handling Using try, except and finally statement:
Exceptions in Python:
When an error occurs in your programme, Python’s many built-in exceptions are raised (something in the programme goes wrong).
The Python interpreter stops the running process when one of these exceptions occurs and transfers control to the caller process until the issue is resolved. If handled improperly, the software will crash.
Consider, for illustration, a programme in which function A calls function B, which in turn calls function C. If an error arises in function C but isn’t handled there, it goes to B before going to A.
If not addressed, an error message appears and our programme abruptly and unexpectedly stops.
Catching Exceptions in Python:
A try statement in Python can be used to manage exceptions.
The try clause contains the crucial operation that can cause an exception. The except clause contains the code that manages exceptions.
Thus, once we have identified the exception, we may decide what actions to take.
We cycle through the values in the randomList list in this application. The try block contains the code that, as was discussed earlier, can lead to an exception.
The unless block is bypassed and normal flow resumes if there is no exception (for last value). But the unless block handles any exceptions that do arise (first and second values).
Here, we use the info() method in the sys module to print the name of the exception. As we can see, a results in ValueError whereas 0 results in ZeroDivisionError.
Catching Specific Exceptions in Python:
In the example given above, the except clause did not contain any specific exceptions.
This is not a suitable programming technique because it will catch every exception and treat each situation uniformly. Which exceptions an except clause should cover can be specified.
A try clause may contain any number of except clauses to address various exceptions, but only one will be carried out in the event of an exception.
Multiple exceptions can be specified in an except clause using a tuple of values.
Raising Exceptions in Python:
Exceptions are produced in Python programming when runtime issues happen. Using the raise keyword, we can manually raise exceptions as well.
If we want to know why an exception was raised, we can optionally give values to the exception.
Python try with else clause:
If the code block inside the attempt executed without any issues, you could occasionally want to run another section of code. You can pair the try statement with the optional else keyword in certain situations.
Note: The previous except clauses do not apply to exceptions in the else clause.
In Python, a finally clause is an optional addition to the try statement. This phrase, which is typically used to release external resources, is always put into effect.
For instance, we might be utilising a file or a Graphical User Interface while connecting via the network to a distant data centre (GUI).
In any of these scenarios, whether the programme ran successfully or not, we must clear away the resource before it terminates. The finally clause carries out these operations (closing a file, shutting a GUI, or disconnecting from the network) to ensure execution.
Python – Error Types
When a statement is not used in accordance with the guidelines, it is the most frequent cause of an error in a Python programme. A syntax error is what we refer to as such. The Python interpreter notifies the user right away, typically along with the cause.
Print is a built-in function in Python 3.x and needs parentheses. This usage is broken in the previous statement, which is why a syntax error is shown.
However, even if a programme doesn’t have any syntax errors, they frequently appear after it has been run. Such a mistake is a runtime exception error. The Python library contains definitions for a number of built-in exceptions.
When attempting to access an item at an invalid index, the IndexError exception is raised.
When a module cannot be found, the ModuleNotFoundError is raised.
3. Key error:
When a key cannot be located, the KeyError is raised.
4. Type error:
When an action or function is used on an object of an improper type, the TypeError exception is raised.
Python error checker:
Python checker makes it possible to examine the grammar of your Python code (Python 3) and identify Python mistakes. The syntax error is highlighted and indicated on the line by this Python code checker tool.
You must copy and paste, drag and drop a Python file, or type directly in the Online Python editor below to review your code before clicking the “Check Python syntax” button.
How to check your Python code’s syntax:
First, drag and drop your Python file into the editor above or manually paste your Python text there.
To begin code checking, you must finally click the “Check Python syntax” button.
Python code can be analysed quickly and easily!
Python is a terrific language when used alone, and understanding its syntax is great and all, but Python’s success isn’t due to its principles. Many fun-to-write languages, like Ruby, Julia, and even R, are similar to Python. Python triumphs thanks to its community and third-party packages. Even though we can accomplish a lot with only a Python installation and the standard library, there is no end to what we can accomplish with all of the third party libraries available today.