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Python Advanced Concepts
Python Advanced Concepts
Basics of Error Handling
Welcome to the first chapter of our journey into error handling in Python! 🎉 Error handling is a critical skill for any programmer, as it allows your programs to respond appropriately to unexpected issues. This chapter covers the types of errors and exceptions you might encounter and how to handle them using the try and except blocks.
Types of Errors and Exceptions in Python
Python categorizes errors into two main types: syntax errors and exceptions.
Syntax Errors
Syntax errors occur when the parser detects an incorrect statement. This could be a typo, a missing parenthesis, or incorrect indentation. Here's an example:
This will result in a syntax error (SyntaxError) because the closing parenthesis is missing.
Exceptions or Run-Time Error
Exceptions are errors that are detected during execution. Common exceptions include:
- IndexError: trying to access an index that does not exist;
- ValueError: passing an argument with the wrong value;
- TypeError: mismatch of data type, such as adding a string to an integer;
- ZeroDivisionError: dividing a number by zero;
- FileNotFoundError: trying to access a file that doesn't exist.
Here is an exception hierarchy where each lower-level error inherits from the one above it. This means that if you catch a higher-level exception, such as Exception, it will also catch all derived 'child' errors. While it's not necessary to know every single error, those highlighted in yellow are the most common and are particularly important to be aware of.
The try, except Block
To handle exceptions effectively, Python uses the try and except blocks. This allows the program to continue even if an error occurs.
Example of try, except Block
Code Description
try Block:
- The try block contains the code that might raise an exception during its execution. In this example, the code attempts to divide the number 10 by zero.
result = 10 / 0: This line of code tries to perform division by zero, which is mathematically undefined and causes Python to raise a ZeroDivisionError.print("The result is", result): This line is supposed to print the result of the division. However, since the division by zero raises an exception, this line will not execute if the error occurs.
except ZeroDivisionError Block:
- The except block specifies how to handle a specific exception that might be raised in the preceding try block. In this case, it is designed to handle the ZeroDivisionismError.
- When the ZeroDivisionError is raised in the try block, execution is immediately passed to this except block.
print("Attempted to divide by zero."): This statement executes when the ZeroDivisionError occurs, informing the user of the issue. This prevents the program from crashing and instead provides a controlled response to the error.
If the division were possible (i.e., dividing by a number other than zero), the print statement within the try block would execute, and the except block would be skipped. The except block only executes when the specific error it is designed to catch is raised.
Let’s practice error handling by writing a script that simulates error conditions and uses the try and except blocks.
Завдання
Write a script that handles different types of errors using basic operations.
#Use comments as helpful tips for solving this task 😉
Все було зрозуміло?
Зміст курсу
Python Advanced Concepts
Python Advanced Concepts
Basics of Error Handling
Welcome to the first chapter of our journey into error handling in Python! 🎉 Error handling is a critical skill for any programmer, as it allows your programs to respond appropriately to unexpected issues. This chapter covers the types of errors and exceptions you might encounter and how to handle them using the try and except blocks.
Types of Errors and Exceptions in Python
Python categorizes errors into two main types: syntax errors and exceptions.
Syntax Errors
Syntax errors occur when the parser detects an incorrect statement. This could be a typo, a missing parenthesis, or incorrect indentation. Here's an example:
This will result in a syntax error (SyntaxError) because the closing parenthesis is missing.
Exceptions or Run-Time Error
Exceptions are errors that are detected during execution. Common exceptions include:
- IndexError: trying to access an index that does not exist;
- ValueError: passing an argument with the wrong value;
- TypeError: mismatch of data type, such as adding a string to an integer;
- ZeroDivisionError: dividing a number by zero;
- FileNotFoundError: trying to access a file that doesn't exist.
Here is an exception hierarchy where each lower-level error inherits from the one above it. This means that if you catch a higher-level exception, such as Exception, it will also catch all derived 'child' errors. While it's not necessary to know every single error, those highlighted in yellow are the most common and are particularly important to be aware of.
The try, except Block
To handle exceptions effectively, Python uses the try and except blocks. This allows the program to continue even if an error occurs.
Example of try, except Block
Code Description
try Block:
- The try block contains the code that might raise an exception during its execution. In this example, the code attempts to divide the number 10 by zero.
result = 10 / 0: This line of code tries to perform division by zero, which is mathematically undefined and causes Python to raise a ZeroDivisionError.print("The result is", result): This line is supposed to print the result of the division. However, since the division by zero raises an exception, this line will not execute if the error occurs.
except ZeroDivisionError Block:
- The except block specifies how to handle a specific exception that might be raised in the preceding try block. In this case, it is designed to handle the ZeroDivisionismError.
- When the ZeroDivisionError is raised in the try block, execution is immediately passed to this except block.
print("Attempted to divide by zero."): This statement executes when the ZeroDivisionError occurs, informing the user of the issue. This prevents the program from crashing and instead provides a controlled response to the error.
If the division were possible (i.e., dividing by a number other than zero), the print statement within the try block would execute, and the except block would be skipped. The except block only executes when the specific error it is designed to catch is raised.
Let’s practice error handling by writing a script that simulates error conditions and uses the try and except blocks.
Завдання
Write a script that handles different types of errors using basic operations.
#Use comments as helpful tips for solving this task 😉
Все було зрозуміло?
