Function call and execution flow in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to call the function greet.

Python

def greet():
    print("Hello!")

greet[1]

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

A()

B[]

C{}

D:

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets or curly braces instead of parentheses.

Forgetting the parentheses and just writing the function name.

The function greet is called using parentheses () after its name.

2fill in blank

medium

Complete the code to return the sum of two numbers from the function.

Python

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

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

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 return the result.

The add function returns the sum of a and b using the plus operator +.

3fill in blank

hard

Fix the error in the function call to print the message.

Python

def say_message(msg):
    print(msg)

say_message[1]

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

Amsg

Bmsg()

CHello!

D"Hello!"

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a variable name without quotes when a string is needed.

Forgetting the parentheses or quotes.

The function say_message needs a string argument inside parentheses and quotes, like "Hello!".

4fill in blank

hard

Fill both blanks to create a function that returns the square of a number and call it.

Python

def square[1]:
    return x[2]2

result = square(5)
print(result)

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

A(x)

B**

C*

Dx

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting parentheses around the parameter.

Using multiplication * instead of exponentiation **.

The function square takes one parameter x (written as (x)) and returns x raised to the power of 2 using **.

5fill in blank

hard

Fill all three blanks to create a function that filters even numbers from a list and returns a new list.

Python

def filter_even[1]:
    return [num for num in numbers if num [2] 2 == 0]

nums = [1, 2, 3, 4, 5]
even_nums = filter_even[3]
print(even_nums)

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

A(numbers)

B%

C(nums)

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using equality == instead of modulo % in the condition.

Forgetting to pass the list argument when calling the function.

The function filter_even takes a list numbers as parameter. It returns a list of numbers where each number modulo 2 (% 2) equals zero. The function is called with the list nums.

Practice

1. What happens when you call a function in Python?

easy

A. The program restarts from the beginning.

B. The program stops running completely.

C. The program jumps to the function's code and runs it.

D. The function code is ignored.

Solution

1. Step 1: Understand function call behavior

   When a function is called, the program temporarily moves to the function's code to execute it.

2. Step 2: Recognize program flow after function

   After the function finishes, the program returns to where it left off and continues running.

3. Final Answer:

   The program jumps to the function's code and runs it. -> Option C

4. Quick Check:

   Function call = program runs function code [OK]

Hint: Calling a function runs its code then returns [OK]

Common Mistakes:

• Thinking the program stops after a function call
• Believing the function code is skipped
• Assuming the program restarts after calling a function

2. Which of the following is the correct way to call a function named greet in Python?

easy

A. greet()

B. call greet()

C. function greet()

D. run greet()

Solution

1. Step 1: Recall Python function call syntax

   In Python, you call a function by writing its name followed by parentheses, like greet().

2. Step 2: Eliminate incorrect options

   The incorrect options use keywords or syntax not used in Python for calling functions.

3. Final Answer:

   greet() -> Option A

4. Quick Check:

   Function call syntax = name + () [OK]

Hint: Call functions by name followed by parentheses [OK]

Common Mistakes:

• Adding extra keywords like 'call' or 'run'
• Using 'function' keyword to call
• Forgetting parentheses after function name

3. What is the output of this code?

def add(x, y):
    return x + y

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

medium

A. 34

B. 7

C. None

D. Error

Solution

1. Step 1: Understand the function behavior

   The function add takes two numbers and returns their sum.

2. Step 2: Calculate the function call result

   Calling add(3, 4) returns 3 + 4 = 7, which is stored in result.

3. Step 3: Print the result

   The print(result) statement outputs 7.

4. Final Answer:

   7 -> Option B

5. Quick Check:

   3 + 4 = 7 [OK]

Hint: Return value is printed, so output is sum 7 [OK]

Common Mistakes:

• Thinking the function prints instead of returns
• Concatenating numbers as strings (34)
• Expecting None because of missing print inside function

4. Find the error in this code:

def greet():
    print("Hello")

print(greet)

medium

A. It prints the function object, not the greeting.

B. SyntaxError due to missing parentheses in function definition.

C. NameError because greet is not defined.

D. IndentationError inside the function.

Solution

1. Step 1: Analyze the print statement

   The code prints greet without parentheses, so it prints the function object, not the result of calling it.

2. Step 2: Understand function call vs reference

   To run the function and print "Hello", it should be print(greet()) with parentheses.

3. Final Answer:

   It prints the function object, not the greeting. -> Option A

4. Quick Check:

   Missing () means function object printed [OK]

Hint: Use parentheses to call function, else prints object [OK]

Common Mistakes:

• Thinking missing parentheses cause syntax error
• Assuming function is not defined
• Confusing function call with function reference

5. Given this code, what will be printed?

def outer():
    def inner():
        return "Inside inner"
    result = inner()
    return result

print(outer())

hard

A. Error

B. inner

C. None

D. "Inside inner"

Solution

1. Step 1: Understand nested function calls

   The function outer defines an inner function inner and calls it, storing its return value.

2. Step 2: Trace the return values

   inner() returns the string "Inside inner", which outer() then returns.

3. Step 3: Print the final returned value

   The print(outer()) statement prints "Inside inner".

4. Final Answer:

   "Inside inner" -> Option D

5. Quick Check:

   Nested call returns inner's string [OK]

Hint: Nested function returns value used by outer function [OK]

Common Mistakes:

• Thinking inner function name prints instead of its return
• Expecting None because inner is nested
• Assuming error due to nested function