File modes and access types in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this code when reading a file?

Consider a file example.txt containing the text "Hello World". What will be printed by the following code?

Python

with open('example.txt', 'r') as f:
    content = f.read(5)
    print(content)

A "Hello World"

B "Hello\n"

C "Hello"

D "World"

💡 Hint

The read(n) method reads n characters from the file starting at the beginning.

The code reads only the first 5 characters from the file, which are "Hello". It does not read the entire file.

❓ Predict Output

intermediate

What happens when opening a file in 'w' mode?

Given a file data.txt that already contains some text, what will be the content of the file after running this code?

Python

with open('data.txt', 'w') as f:
    f.write('New content')

A The code will raise an error because the file exists.

B The file will contain the old content plus "New content" appended.

C The file will be unchanged.

D The file will contain "New content" only.

💡 Hint

Opening a file in 'w' mode clears its content before writing.

Mode 'w' opens the file for writing and truncates it to zero length, so old content is removed.

❓ Predict Output

advanced

What error does this code raise when opening a non-existent file?

What error will this code raise if missing.txt does not exist?

Python

with open('missing.txt', 'r') as f:
    data = f.read()

A FileNotFoundError

B PermissionError

C IsADirectoryError

D No error, file is created automatically

💡 Hint

Opening a file in read mode requires the file to exist.

Trying to open a non-existent file in 'r' mode raises FileNotFoundError.

❓ Predict Output

advanced

What is the content of the file after this code runs?

Assume log.txt initially contains "Start\n". What will be the content after running this code?

Python

with open('log.txt', 'a') as f:
    f.write('End\n')

A "End\n"

B "Start\nEnd\n"

C "Start\n"

D The file is empty

💡 Hint

Mode 'a' appends to the file without deleting existing content.

Opening in append mode adds new text at the end, so original content remains.

🧠 Conceptual

expert

Which file mode allows both reading and writing without truncating the file?

Choose the file mode that opens a file for both reading and writing, but does not erase the existing content when opened.

A "r+"

B "w+"

C "a+"

D "x+"

💡 Hint

One mode allows reading and writing and keeps existing content intact.

Mode r+ opens for reading and writing without truncating. w+ truncates, a+ appends, x+ creates new file only.