Quiz: Python file handling and exceptions

What is file handling in Python?

File handling refers to the process of creating, reading, updating, and deleting files in Python using built-in functions.

How do you open a file in Python?

Use the built-in function `open(filename, mode)` where mode can be 'r', 'w', 'a', etc.

True or False: 'r' mode overwrites a file.

False. 'r' mode opens a file for reading only; it cannot overwrite.

Fill in the blank: To close a file, use the method ______.

.close()

What is the purpose of exceptions in Python?

Exceptions allow handling errors gracefully, preventing program crashes and managing unexpected situations.

What is the 'with' statement used for?

The 'with' statement simplifies file handling by automatically closing the file after the block is executed.

Compare 'w' and 'a' modes.

'w': Write mode, overwrites existing files. 'a': Append mode, adds to existing files.

Cause → Effect: What happens when you try to open a non-existent file in 'r' mode?

An IOError is raised, indicating the file cannot be found.

How do you read contents of a file?

Use `file.read()` to read all contents or `file.readline()` for one line at a time.

What is a try-except block?

A try-except block is used to catch and handle exceptions in Python, providing a way to respond to errors.

What does the 'finally' block do?

The 'finally' block executes code regardless of whether an exception was raised, often used for cleanup.

How to write data to a file?

Open a file in 'w' or 'a' mode, then use `file.write(data)` to write the desired content.

What does 'with open' do in Python?

Automatically handles opening and closing files. - Ensures files are properly closed, even if an error occurs.

True or False: Exceptions crash the program.

False - Exceptions can be caught and handled using try-except blocks.

List two built-in exceptions in Python.

1. ValueError 2. FileNotFoundError

Fill in the blank: To read a file, use ______.

file.read()

How to handle multiple exceptions?

Use a tuple in the except clause: try: ... except (TypeError, ValueError): ...

What is the purpose of 'finally'?

'finally' block always executes after try-except, regardless of exceptions, for cleanup actions.

Compare 'read()' vs 'readline()'.

'read()' reads the entire file; 'readline()' reads one line at a time.

Cause → Effect: FileNotFoundError occurs when...

...you try to open a file that does not exist.

Example: Write to a file in Python.

with open('output.txt', 'w') as file: file.write('Hello, World!')

What is a context manager?

A construct that simplifies resource management, ensuring resources are properly managed.

True or False: You must manually close a file opened with 'with'.

False - 'with' automatically closes the file.

Describe the role of 'try' in error handling.

'try' block allows you to test a block of code for errors, catching exceptions.