Appending data to files in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Appending text to a file

What will be the content of the file example.txt after running this code?

Assume example.txt initially contains the text: Hello

Python

with open('example.txt', 'a') as f:
    f.write(' World')

A Hello

B Hello\nWorld

C World

D Hello World

💡 Hint

Appending adds text at the end without removing existing content.

The mode 'a' opens the file for appending. The write adds ' World' right after 'Hello' without adding a new line.

❓ Predict Output

intermediate

Appending with newline character

What will be the content of log.txt after running this code?

Assume log.txt initially contains:
Start

Python

with open('log.txt', 'a') as file:
    file.write('\nEnd')

A StartEnd

B \nEnd

C Start\nEnd

D Start\n\nEnd

💡 Hint

The '\n' adds a new line before 'End'.

The '\n' character creates a new line, so 'End' appears on the line after 'Start'.

❓ Predict Output

advanced

Appending binary data to a file

What will be the output of this code snippet?

Assume data.bin initially contains bytes: b'\x01\x02'

Python

with open('data.bin', 'ab') as f:
    f.write(b'\x03\x04')

with open('data.bin', 'rb') as f:
    content = f.read()
print(content)

A b'\x01\x02\x03\x04'

B b'\x03\x04'

C b'\x01\x02'

D b''

💡 Hint

Appending in binary mode adds bytes at the end.

Opening with 'ab' appends bytes to the file. Reading after shows original plus appended bytes.

❓ Predict Output

advanced

Appending text with encoding

What will be the content of unicode.txt after running this code?

Assume unicode.txt initially contains: café

Python

with open('unicode.txt', 'a', encoding='utf-8') as f:
    f.write(' ☕')

with open('unicode.txt', encoding='utf-8') as f:
    content = f.read()
print(content)

A café ☕

B café☕

C café \u2615

D café

💡 Hint

Appending adds the coffee cup emoji with a space before it.

The write adds a space and the emoji after the existing text. Reading shows combined text.

🧠 Conceptual

expert

File pointer position after appending

After opening a file in append mode ('a'), what is the position of the file pointer before writing?

Choose the correct statement.

A The file pointer is at a random position, so writes may overwrite or append.

B The file pointer is at the end of the file, so writes always add data after existing content.

C The file pointer is at the beginning, so writes overwrite existing content.

D The file pointer is at the middle of the file, so writes insert data there.

💡 Hint

Append mode means adding data after existing content.

In append mode, the file pointer is always moved to the end before each write, so data is added after existing content.