File system interaction basics in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What Python function is used to open a file for reading or writing?

The open() function is used to open a file. You can specify the mode like 'r' for reading or 'w' for writing.

beginner

What does the mode 'r' mean when opening a file?

Mode 'r' means open the file for reading only. The file must exist or Python will give an error.

beginner

How do you properly close a file after opening it?

You call the close() method on the file object, like file.close(). This frees system resources.

intermediate

What is the advantage of using a with statement when working with files?

Using with automatically closes the file when the block ends, even if errors happen. It keeps code safe and clean.

beginner

How do you write text to a file in Python?

Open the file in write mode ('w'), then use file.write('your text') to add text. Remember to close the file or use with.

Which mode opens a file for appending data without deleting existing content?

A 'w'

B 'r'

C 'x'

D 'a'

Mode 'a' opens the file for appending. It adds new data at the end without removing existing content.

What happens if you try to open a non-existent file in 'r' mode?

A Python creates a new empty file

B Python raises an error

C Python opens the file in write mode

D Python ignores the request

Opening a file in 'r' mode requires the file to exist. If it doesn't, Python raises a FileNotFoundError.

Which method reads the entire content of a file as a string?

A read()

B write()

C close()

D open()

The read() method reads all the content from the file and returns it as a string.

Why is it better to use 'with open(...) as file:' instead of just open()?

A It automatically closes the file after use

B It makes the file read-only

C It speeds up file reading

D It encrypts the file content

Using 'with' ensures the file is closed automatically, even if errors occur, preventing resource leaks.

What does the 'w' mode do when opening a file?

A Reads the file

B Appends to the file

C Writes to the file, erasing existing content

D Creates a new file only if it doesn't exist

Mode 'w' opens the file for writing and erases any existing content before writing.

Explain how to safely read the contents of a text file in Python.

Think about how to open, read, and close a file safely.

Describe the difference between 'w' and 'a' modes when opening a file.

Consider what happens to existing content in each mode.