What are Exceptions?
Definition and Purpose
Exceptions are events that disrupt the normal flow of a program. They are used to manage errors or other exceptional conditions in a controlled way. When an error occurs, an exception is raised, allowing the program to handle it gracefully rather than crashing.
Common Exceptions in Python
ValueError: Raised when a function receives an argument of the right type but inappropriate value.TypeError: Occurs when an operation is applied to an object of inappropriate type.IndexError: Triggered when attempting to access an index that is out of range in a list.KeyError: Raised when trying to access a dictionary with a non-existent key.ZeroDivisionError: Occurs when a division by zero is attempted.
Importance of Exception Handling
Handling exceptions allows developers to:
- Prevent program crashes.
- Provide informative error messages to users.
- Maintain the program’s flow by catching and resolving errors.
How Exceptions Work
When an error is detected, Python raises an exception and stops executing the current code block. The exception is propagated up the call stack until it is caught and handled, or the program terminates if not handled.
Types of Built-in Exceptions
Python provides numerous built-in exceptions, which are organized in a hierarchy. Some key exceptions include:
ArithmeticError: Base class for errors in numeric calculations.FileNotFoundError: Raised when a file operation fails due to the file not being found.ImportError: Occurs when an import statement fails to find the module definition.
