Methods with return values in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return the sum of two numbers.

Python

def add_numbers(a, b):
    return a [1] b

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

A-

B/

C+

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using subtraction or multiplication instead of addition.

Forgetting to use the return statement.

The return statement sends back the sum of a and b using the + operator.

2fill in blank

medium

Complete the code to return the length of the given string.

Python

def string_length(s):
    return [1](s)

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

Alen

Bsize

Ccount

Dlength

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent functions like size() or length().

Trying to use string methods that don't return length.

The built-in function len() returns the number of characters in a string.

3fill in blank

hard

Fix the error in the method to return the square of a number.

Python

def square(num):
    result = num [1] num
    return result

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

A-

B*

C+

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition or subtraction instead of multiplication.

Forgetting to multiply the number by itself.

To get the square, multiply the number by itself using the * operator.

4fill in blank

hard

Fill both blanks to create a method that returns a dictionary with words as keys and their lengths as values, but only for words longer than 3 letters.

Python

def word_lengths(words):
    return {word: [1] for word in words if len(word) [2] 3}

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

Alen(word)

Bword

C>

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using the word itself as the value instead of its length.

Using the wrong comparison operator in the condition.

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

5fill in blank

hard

Fill all three blanks to create a method that returns a dictionary with uppercase keys and values only for items with positive values.

Python

def filter_and_uppercase(data):
    return { [1]: [2] for k, v in data.items() if v [3] 0 }

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

Ak.upper()

Bv

C>

Dk

Attempts:

3 left

💡 Hint

Common Mistakes

Not converting keys to uppercase.

Using wrong comparison operators or filtering conditions.

The keys are converted to uppercase with k.upper(), values are kept as v, and only items with values greater than 0 are included using >.

Practice

1. What does a method with a return statement do in Python?

easy

A. It sends a value back to where the method was called.

B. It prints a value on the screen.

C. It stops the program immediately.

D. It creates a new variable automatically.

Solution

1. Step 1: Understand the purpose of return

   The return statement sends a value back from the method to the caller.

2. Step 2: Differentiate from printing or stopping

   Printing shows output but does not send a value back; stopping ends execution.

3. Final Answer:

   It sends a value back to where the method was called. -> Option A

4. Quick Check:

   Method return = sends value back [OK]

Hint: Return sends value back, print shows it only [OK]

Common Mistakes:

• Confusing return with print
• Thinking return stops the program
• Believing return creates variables

2. Which of the following is the correct syntax for a method that returns the sum of two numbers a and b?

easy

A. def add(a, b): return a - b

B. def add(a, b): print(a + b)

C. def add(a, b): return a + b

D. def add(a, b): a + b

Solution

1. Step 1: Identify correct return usage

   The method must use return to send back the sum a + b.

2. Step 2: Check each option

   The version with return a - b returns the difference. The version with print(a + b) prints but returns None. The version with just a + b lacks return. Only def add(a, b): return a + b correctly returns the sum.

3. Final Answer:

   def add(a, b): return a + b -> Option C

4. Quick Check:

   Return sum = def add(a, b): return a + b [OK]

Hint: Return must be followed by value to send back [OK]

Common Mistakes:

• Using print instead of return
• Omitting return keyword
• Returning wrong expression

3. What is the output of this code?

def multiply(x, y):
    return x * y

result = multiply(3, 4)
print(result)

medium

A. 7

B. 12

C. 34

D. None

Solution

1. Step 1: Understand the method call

   The method multiply returns the product of 3 and 4, which is 12.

2. Step 2: Print the returned value

   The variable result stores 12, so print(result) outputs 12.

3. Final Answer:

   12 -> Option B

4. Quick Check:

   3 * 4 = 12 [OK]

Hint: Multiply inputs, return result, print shows it [OK]

Common Mistakes:

• Adding instead of multiplying
• Printing None by missing return
• Confusing string concatenation with multiplication

4. Find the error in this method and choose the correct fix:

def greet(name):
    print("Hello, " + name)

message = greet("Alice")
print(message)

medium

A. Remove the argument name from the method.

B. Add print before calling greet.

C. Change message to greet in the last print.

D. Change print to return inside the method.

Solution

1. Step 1: Identify the problem with return value

   The method prints but does not return a value, so message is None.

2. Step 2: Fix by returning the greeting string

   Replace print with return to send the greeting back.

3. Final Answer:

   Change print to return inside the method. -> Option D

4. Quick Check:

   Return greeting to assign message [OK]

Hint: Use return to get value, not print [OK]

Common Mistakes:

• Expecting print to return a value
• Removing needed parameters
• Changing variable names incorrectly

5. You want to write a method that returns a dictionary with keys as numbers from 1 to n and values as their squares. Which method below correctly does this?

hard

A. def squares(n):
result = {}
for i in range(1, n+1):
result[i] = i * i
return result

B. def squares(n):
result = []
for i in range(n):
result.append(i * i)
return result

C. def squares(n):
return {i: i + i for i in range(1, n)}

D. def squares(n):
for i in range(1, n+1):
print(i * i)

Solution

1. Step 1: Understand the requirement

   The method must return a dictionary with keys 1 to n and values as squares.

2. Step 2: Check each option

   The loop building result = {}, setting result[i] = i * i for i in range(1, n+1), and returning result is correct. Returning a list fails. The comprehension {i: i + i for i in range(1, n)} uses doubles instead of squares and misses key n. Printing without returning fails.

3. Final Answer:

   def squares(n): result = {} for i in range(1, n+1): result[i] = i * i return result -> Option A

4. Quick Check:

   Return dict with squares = def squares(n): result = {} for i in range(1, n+1): result[i] = i * i return result [OK]

Hint: Return dict with keys and squares using loop [OK]

Common Mistakes:

• Returning list instead of dict
• Using wrong range limits
• Printing instead of returning