Elif ladder execution in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if a number is positive.

Python

if num [1] 0:
    print("Positive number")

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 for negative numbers.

Using '==' checks only if number equals zero, not positive.

The condition num > 0 checks if the number is positive.

2fill in blank

medium

Complete the code to print "Zero" when num is zero.

Python

if num > 0:
    print("Positive")
elif num [1] 0:
    print("Zero")

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

A>

B==

C!=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' will check for any number except zero.

Using '<' or '>' will not correctly identify zero.

The condition num == 0 checks if the number is exactly zero.

3fill in blank

hard

Fix the error in the elif condition to check if num is negative.

Python

if num > 0:
    print("Positive")
elif num [1] 0:
    print("Negative")

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

A<

B==

C>

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' checks only for zero, not negative numbers.

Using '!=' checks for any number except zero, not specifically negative.

The condition num < 0 correctly checks if the number is negative.

4fill in blank

hard

Fill both blanks to complete the elif ladder that prints the sign of num.

Python

if num [1] 0:
    print("Positive")
elif num [2] 0:
    print("Negative")

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

A>

B<

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the operators will give wrong results.

Using '==' in these places will not check for positive or negative.

The first condition checks if num > 0 for positive numbers.
The second checks if num < 0 for negative numbers.

5fill in blank

hard

Fill all three blanks to complete the elif ladder that prints the sign or zero.

Python

if num [1] 0:
    print("Positive")
elif num [2] 0:
    print("Negative")
else:
    print("[3]")

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

A>

B<

CZero

DPositive

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong operators in conditions.

Printing wrong string in else block.

The code checks if num > 0 for positive, num < 0 for negative, and prints "Zero" otherwise.

Practice

1.

What does an elif ladder do in Python?

easy

A. Only checks the last condition in the ladder

B. Runs all conditions regardless of their truth value

C. Checks multiple conditions in order and runs the first true block

D. Skips all conditions and runs the else block always

Solution

1. Step 1: Understand the purpose of elif ladder

   An elif ladder checks conditions one by one in order.

2. Step 2: Identify behavior on true condition

   It stops checking further once it finds the first true condition and runs that block.

3. Final Answer:

   Checks multiple conditions in order and runs the first true block -> Option C

4. Quick Check:

   Elif ladder = first true condition runs [OK]

Hint: Elif stops at first true condition found [OK]

Common Mistakes:

• Thinking all conditions run
• Believing else runs before elif
• Assuming elif checks last only

2.

Which of these is the correct syntax for an elif statement in Python?

if x > 10:
    print("Big")
____ x > 5:
    print("Medium")
else:
    print("Small")

easy

A. elif

B. else if

C. elseif

D. elif:

Solution

1. Step 1: Recall Python elif syntax

   Python uses 'elif' without spaces or colon after it.

2. Step 2: Check options for correct keyword

   Only 'elif' is correct; 'else if' and 'elseif' are invalid in Python.

3. Final Answer:

   elif -> Option A

4. Quick Check:

   Python elif keyword = elif [OK]

Hint: Use 'elif' exactly, no spaces or colon after it [OK]

Common Mistakes:

• Writing 'else if' like other languages
• Adding colon after elif keyword
• Using 'elseif' as one word

3.

What will be the output of this code?

score = 75
if score >= 90:
    print("A")
elif score >= 80:
    print("B")
elif score >= 70:
    print("C")
else:
    print("F")

medium

A. A

B. B

C. F

D. C

Solution

1. Step 1: Check conditions in order with score=75

   score >= 90? No. score >= 80? No. score >= 70? Yes.

2. Step 2: Print output for first true condition

   Prints "C" and stops checking further.

3. Final Answer:

   C -> Option D

4. Quick Check:

   75 >= 70 = True, prints C [OK]

Hint: Check conditions top to bottom, stop at first true [OK]

Common Mistakes:

• Choosing B or A ignoring order
• Thinking else runs when elif true
• Confusing >= with >

4.

Find the error in this elif ladder code:

num = 10
if num < 5:
    print("Small")
elif num > 5
    print("Big")
else:
    print("Medium")

medium

A. Missing colon after elif condition

B. Wrong indentation of print statements

C. Using else without condition

D. Using < instead of > in if

Solution

1. Step 1: Check syntax of elif line

   Line 'elif num > 5' is missing a colon at the end.

2. Step 2: Identify correct syntax for elif

   Elif condition must end with a colon ':' to be valid.

3. Final Answer:

   Missing colon after elif condition -> Option A

4. Quick Check:

   Elif line needs colon ':' [OK]

Hint: Always put colon after if/elif/else lines [OK]

Common Mistakes:

• Forgetting colon after elif
• Misaligning indentation
• Thinking else needs condition

5.

Given this code, what will be printed if value = 0?

value = 0
if value:
    print("True")
elif value == 0:
    print("Zero")
else:
    print("False")

hard

A. True

B. Zero

C. False

D. No output

Solution

1. Step 1: Evaluate if condition with value=0

   In Python, 0 is treated as False, so 'if value:' is False.

2. Step 2: Check elif condition

   'elif value == 0:' is True, so it prints "Zero" and stops.

3. Final Answer:

   Zero -> Option B

4. Quick Check:

   0 is falsy, elif value==0 True [OK]

Hint: Remember 0 is False, check explicit elif next [OK]

Common Mistakes:

• Thinking if value: is True for 0
• Ignoring elif condition
• Assuming else runs always