If–else execution flow in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print "Yes" if the number is greater than 10.

Python

number = 15
if number [1] 10:
    print("Yes")

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

A<

B<=

C>

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of > will check the wrong condition.

The condition should check if number is greater than 10 using the > operator.

2fill in blank

medium

Complete the code to print "Even" if the number is divisible by 2.

Python

number = 8
if number [1] 2 == 0:
    print("Even")

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

A%

B//

C**

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using // will do floor division, not remainder.

The modulo operator % gives the remainder. If number % 2 == 0, the number is even.

3fill in blank

hard

Fix the error in the if statement to check if age is at least 18.

Python

age = 20
if age [1] 18:
    print("Adult")

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

A>=

B<=

C=>

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using => is a syntax error in Python.

The correct operator to check if age is greater than or equal to 18 is >=.

4fill in blank

hard

Fill both blanks to print "Positive" if x is greater than 0 and "Non-positive" otherwise.

Python

x = 5
if x [1] 0:
    print("Positive")
else:
    print("[2]")

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

A>

BNegative

CNon-positive

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of > will reverse the logic.

Printing "Negative" is not correct because zero is also non-positive.

The condition checks if x is greater than 0 using >. If not, it prints "Non-positive".

5fill in blank

hard

Fill all three blanks to print "Fizz" if number divisible by 3, "Buzz" if divisible by 5, else print the number.

Python

number = 15
if number [1] 3 == 0:
    print("[2]")
elif number [3] 5 == 0:
    print("Buzz")
else:
    print(number)

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

A%

BFizz

C==

D//

Attempts:

3 left

💡 Hint

Common Mistakes

Using // instead of % will not check divisibility correctly.

Use modulo % to check divisibility. Print "Fizz" if divisible by 3, "Buzz" if divisible by 5.

Practice

1. What does an if-else statement do in Python?

easy

A. It chooses between two paths based on a condition.

B. It repeats code multiple times.

C. It defines a function.

D. It creates a list.

Solution

1. Step 1: Understand the purpose of if-else

   An if-else statement lets the program decide which code to run based on a condition being true or false.

2. Step 2: Compare with other options

   Repeating code is done by loops, functions define reusable code blocks, and lists store multiple items, so these are not correct.

3. Final Answer:

   It chooses between two paths based on a condition. -> Option A

4. Quick Check:

   If-else = choose path [OK]

Hint: If-else picks one of two paths based on condition [OK]

Common Mistakes:

• Confusing if-else with loops
• Thinking if-else creates data structures
• Mixing if-else with function definitions

2. Which of the following is the correct syntax for an if-else statement in Python?

easy

A. if x > 0:
print('Positive')
else:
print('Non-positive')

B. if x > 0 then print('Positive') else print('Non-positive')

C. if (x > 0) { print('Positive'); } else { print('Non-positive'); }

D. if x > 0
print('Positive')
else
print('Non-positive')

Solution

1. Step 1: Recall Python if-else syntax

   Python uses a colon after the condition and indentation for the code blocks.

2. Step 2: Check each option

   if x > 0: print('Positive') else: print('Non-positive') uses colons and indentation correctly. if x > 0 then print('Positive') else print('Non-positive') uses 'then' which is not Python syntax. if (x > 0) { print('Positive'); } else { print('Non-positive'); } uses braces and semicolons, which are for other languages. if x > 0 print('Positive') else print('Non-positive') misses colons and indentation.

3. Final Answer:

   if x > 0: print('Positive') else: print('Non-positive') -> Option A

4. Quick Check:

   Colon + indent = correct if-else [OK]

Hint: Remember colons and indentation for if-else in Python [OK]

Common Mistakes:

• Using 'then' keyword
• Forgetting colons after if and else
• Not indenting code blocks

3. What will be the output of this code?

age = 18
if age >= 18:
    print('Adult')
else:
    print('Minor')

medium

A. Minor

B. Adult

C. 18

D. No output

Solution

1. Step 1: Evaluate the condition age >= 18

   Since age is 18, the condition age >= 18 is true.

2. Step 2: Determine which block runs

   Because the condition is true, the code inside the if block runs, printing 'Adult'.

3. Final Answer:

   Adult -> Option B

4. Quick Check:

   Condition true -> print 'Adult' [OK]

Hint: Check if condition is true or false to pick output [OK]

Common Mistakes:

• Assuming >= means less than
• Printing else block by mistake
• Confusing output with variable value

4. Find the error in this code:

num = 5
if num > 0
    print('Positive')
else:
    print('Non-positive')

medium

A. Variable 'num' is not defined

B. Wrong indentation on print statements

C. Missing colon ':' after 'if num > 0' line

D. 'else' should be 'elif' here

Solution

1. Step 1: Check syntax of if statement

   The if statement must end with a colon ':' to mark the start of the block.

2. Step 2: Identify the missing colon

   The code misses the colon after 'if num > 0', causing a syntax error.

3. Final Answer:

   Missing colon ':' after 'if num > 0' line -> Option C

4. Quick Check:

   Colon needed after if condition [OK]

Hint: Always put colon after if condition [OK]

Common Mistakes:

• Forgetting colon after if
• Confusing else with elif
• Incorrect indentation

5. You want to write a program that prints 'Even' if a number is even, and 'Odd' if it is odd. Which code correctly uses if-else to do this?

hard

A. num = 4
if num % 2:
print('Even')
else:
print('Odd')

B. num = 4
if num / 2 == 0:
print('Even')
else:
print('Odd')

C. num = 4
if num % 2 != 0:
print('Even')
else:
print('Odd')

D. num = 4
if num % 2 == 0:
print('Even')
else:
print('Odd')

Solution

1. Step 1: Understand how to check even numbers

   A number is even if dividing by 2 leaves no remainder, so num % 2 == 0 is true for even numbers.

2. Step 2: Check each option's condition

   num = 4 if num % 2 == 0: print('Even') else: print('Odd') correctly uses num % 2 == 0. num = 4 if num / 2 == 0: print('Even') else: print('Odd') uses division instead of modulo, which is wrong. num = 4 if num % 2: print('Even') else: print('Odd') treats nonzero remainder as even, which is incorrect. num = 4 if num % 2 != 0: print('Even') else: print('Odd') reverses the logic.

3. Final Answer:

   num = 4 if num % 2 == 0: print('Even') else: print('Odd') -> Option D

4. Quick Check:

   Modulo equals zero means even [OK]

Hint: Use 'num % 2 == 0' to check even numbers [OK]

Common Mistakes:

• Using division instead of modulo
• Reversing even and odd logic
• Checking truthiness of modulo without comparison