Reading file data in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the basic Python command to open a file for reading?

Use open('filename', 'r') to open a file in read mode.

beginner

How do you read the entire content of a file at once?

Use the read() method on the file object, like file.read().

intermediate

What does the with statement do when reading files?

It automatically opens and closes the file, making sure resources are freed even if errors happen.

beginner

How can you read a file line by line in Python?

Use a loop like for line in file: to read one line at a time.

beginner

What happens if you try to open a file that does not exist in read mode?

Python raises a FileNotFoundError because the file cannot be found.

Which mode should you use to open a file for reading in Python?

A 'w'

B 'r'

C 'a'

D 'x'

The 'r' mode opens a file for reading only.

What does the read() method do?

A Writes data to the file

B Reads one line from the file

C Closes the file

D Reads the entire file content as a string

read() reads the whole file content at once.

Why is it good to use with open(...) when reading files?

A It automatically closes the file after reading

B It speeds up reading

C It writes data to the file

D It creates a new file

Using with ensures the file is closed properly.

How can you read a file line by line?

A Using a for loop: <code>for line in file:</code>

B Using <code>file.write()</code>

C Using <code>file.close()</code>

D Using <code>open('file', 'w')</code>

A for loop over the file object reads it line by line.

What error occurs if you open a non-existent file in read mode?

A ValueError

B TypeError

C FileNotFoundError

D IndexError

Trying to read a missing file raises FileNotFoundError.

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

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

What are the common errors you might face when reading a file and how to handle them?

Consider what happens if the file is missing or inaccessible.