Docstrings and documentation in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a docstring that describes the function.

Python

def greet(name):
    [1]
    return f"Hello, {name}!"

Drag options to blanks, or click blank then click option'

Aprint("Hello")

B# This function greets the user

C"""Return a greeting message."""

D'''Print greeting'''

Attempts:

3 left

💡 Hint

Common Mistakes

Using comments (#) instead of docstrings.

Using single quotes instead of triple double quotes.

Placing the docstring outside the function.

The correct docstring uses triple double quotes and describes what the function does.

2fill in blank

medium

Complete the code to add a docstring that explains the parameters.

Python

def add(a, b):
    [1]
    return a + b

Drag options to blanks, or click blank then click option'

A"""Add two numbers. Args: a (int): First number. b (int): Second number. Returns: int: Sum of a and b. """

B# Adds a and b

C"""Add two numbers and return the result."""

D'''Sum two values'''

Attempts:

3 left

💡 Hint

Common Mistakes

Not explaining parameters in the docstring.

Using comments instead of docstrings.

Missing the Returns section.

The correct docstring explains the function, its parameters, and the return value clearly.

3fill in blank

hard

Fix the error in the docstring format.

Python

def multiply(x, y):
    [1]
    return x * y

Drag options to blanks, or click blank then click option'

A"""Multiply two numbers and return the product."""

B"Multiply two numbers and return the product."

C'''Multiply two numbers and return the product'''

D# Multiply two numbers

Attempts:

3 left

💡 Hint

Common Mistakes

Using single quotes instead of triple double quotes.

Using comments instead of docstrings.

Not enclosing the docstring properly.

The correct docstring uses triple double quotes to properly format the docstring.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that documents word lengths for words longer than 3 characters.

Python

words = ['apple', 'bat', 'carrot', 'dog']
lengths = {word: [1] for word in words if len(word) [2] 3}

Drag options to blanks, or click blank then click option'

Alen(word)

B<=

C>

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong comparison operator.

Using the word itself instead of its length.

Not filtering words correctly.

The dictionary comprehension uses len(word) to get length and filters words with length greater than 3.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase words to their lengths if length is greater than 4.

Python

words = ['tree', 'house', 'car', 'elephant']
result = [1]: [2] for word in words if len(word) [3] 4

Drag options to blanks, or click blank then click option'

Aword.upper()

Blen(word)

C>

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using the word itself instead of uppercase.

Using wrong comparison operator.

Mixing keys and values in the comprehension.

The comprehension maps uppercase words to their lengths, filtering words longer than 4 characters.

Practice

1. What is the main purpose of a docstring in Python?

easy

A. To store variable values

B. To execute code automatically

C. To explain what a function, class, or module does

D. To import external libraries

Solution

1. Step 1: Understand what docstrings are

   Docstrings are special strings placed right after function, class, or module definitions to describe their purpose.

2. Step 2: Identify the purpose of docstrings

   They help explain what the code does, making it easier for others and yourself to understand.

3. Final Answer:

   To explain what a function, class, or module does -> Option C

4. Quick Check:

   Docstrings = Explanation [OK]

Hint: Docstrings describe code purpose inside triple quotes [OK]

Common Mistakes:

• Thinking docstrings run code
• Confusing docstrings with comments
• Using docstrings to store data

2. Which of the following is the correct way to write a docstring for a function in Python?

easy

A. def func():
// This is a docstring

B. def func():
# This is a docstring

C. def func():
"This is a comment"

D. def func():
'''This function does something'''

Solution

1. Step 1: Identify correct docstring syntax

   Docstrings use triple quotes (''' or """) placed immediately after the function header.

2. Step 2: Check each option

   def func(): '''This function does something''' uses triple single quotes right after the function header, which is correct. Options B and C use comments or double quotes incorrectly. def func(): // This is a docstring uses // which is not valid in Python.

3. Final Answer:

   def func(): '''This function does something''' -> Option D

4. Quick Check:

   Triple quotes after function = docstring [OK]

Hint: Docstrings use triple quotes right after function header [OK]

Common Mistakes:

• Using # instead of triple quotes
• Using single or double quotes only
• Placing docstring before function header

3. What will be the output of the following code?

def greet():
    '''Return a greeting message.'''
    return "Hello!"

print(greet.__doc__)

medium

A. Return a greeting message.

B. None

C. Hello!

D. SyntaxError

Solution

1. Step 1: Understand __doc__ attribute

   The __doc__ attribute of a function returns its docstring, which is the string inside triple quotes right after the function header.

2. Step 2: Check the function's docstring

   The function greet has the docstring 'Return a greeting message.'. So, greet.__doc__ will output this string.

3. Final Answer:

   Return a greeting message. -> Option A

4. Quick Check:

   Function.__doc__ = docstring text [OK]

Hint: Use function.__doc__ to get its docstring text [OK]

Common Mistakes:

• Expecting function return value instead of docstring
• Confusing __doc__ with print output
• Assuming __doc__ is None if no docstring

4. Identify the error in the following code snippet:

def add(a, b):
    """Add two numbers and return the result."""
    return a + b

medium

A. Docstring should use single quotes

B. Missing closing triple quotes for the docstring

C. Incorrect indentation of return statement

D. Function missing return statement

Solution

1. Step 1: Check docstring syntax

   The docstring starts with triple double quotes """ but does not have a closing triple quote before the return statement.

2. Step 2: Identify the error caused

   Without closing triple quotes, Python treats the return line as part of the string, causing a syntax error.

3. Final Answer:

   Missing closing triple quotes for the docstring -> Option B

4. Quick Check:

   Docstrings need opening and closing triple quotes [OK]

Hint: Always close triple quotes in docstrings [OK]

Common Mistakes:

• Forgetting to close triple quotes
• Indenting return inside docstring
• Using single quotes inconsistently

5. You want to write a docstring for a function that calculates the area of a rectangle. Which of the following docstrings best follows good documentation practice?

hard

A. """Calculate the area of a rectangle given width and height.

Parameters:
width (float): The width of the rectangle.
height (float): The height of the rectangle.

Returns:
float: The area of the rectangle."""

B. """Calculate area."""

C. """Area function"""

D. """Returns width * height"""

Solution

1. Step 1: Understand good docstring content

   A good docstring clearly explains what the function does, its parameters, and what it returns.

2. Step 2: Compare options

   """Calculate the area of a rectangle given width and height. Parameters: width (float): The width of the rectangle. height (float): The height of the rectangle. Returns: float: The area of the rectangle.""" provides a clear description, lists parameters with types, and explains the return value. Other options are too short or vague.

3. Final Answer:

   """Calculate the area of a rectangle given width and height. Parameters: width (float): The width of the rectangle. height (float): The height of the rectangle. Returns: float: The area of the rectangle.""" -> Option A

4. Quick Check:

   Good docstrings = clear + parameters + return [OK]

Hint: Include purpose, parameters, and return in docstrings [OK]

Common Mistakes:

• Writing too short or vague docstrings
• Not mentioning parameters or return values
• Using incomplete sentences