Ternary conditional expression in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assign 'Yes' if x is greater than 10, otherwise 'No'.

Python

result = 'Yes' if x [1] 10 else 'No'

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

A<

B==

C>

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' changes the condition meaning.

Using '==' checks equality, not greater than.

The ternary expression checks if x > 10. If true, it assigns 'Yes', else 'No'.

2fill in blank

medium

Complete the code to assign 'Even' if num is divisible by 2, else 'Odd'.

Python

parity = 'Even' if num [1] 2 == 0 else 'Odd'

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

A//

B%

C**

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '//' which is floor division, not remainder.

Using '+' or '**' which are not related to divisibility.

The modulus operator '%' gives the remainder. If num % 2 == 0, num is even.

3fill in blank

hard

Fix the error in the ternary expression to assign 'Adult' if age is 18 or more, else 'Minor'.

Python

status = 'Adult' if age [1] 18 else 'Minor'

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

A==

B<=

C!=

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' reverses the condition meaning.

Using '==' only checks if age equals 18, not more.

The correct comparison operator is '>=' to check if age is 18 or more.

4fill in blank

hard

Fill both blanks to create a ternary expression that assigns 'Pass' if score is 50 or more, else 'Fail'.

Python

result = 'Pass' if score [1] 50 else [2]

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

A>=

B'Fail'

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' in the condition reverses the logic.

Not using quotes around 'Fail' causes syntax errors.

The condition uses '>=' to check if score is 50 or more. The else part assigns 'Fail'.

5fill in blank

hard

Fill all three blanks to create a ternary expression that assigns the uppercase of name if is_upper is True, else the lowercase.

Python

formatted = name.[1]() if is_upper [2] True else name.[3]()

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

Aupper

B==

Clower

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' instead of '==' changes the condition meaning.

Mixing up 'upper' and 'lower' methods.

The method upper() converts to uppercase, lower() to lowercase. The condition checks if is_upper == True.

Practice

1. What does the ternary conditional expression x if condition else y do in Python?

easy

A. Returns y if condition is True, otherwise returns x.

B. Always returns x regardless of condition.

C. Returns x if condition is True, otherwise returns y.

D. Raises an error if condition is False.

Solution

1. Step 1: Understand the ternary syntax

   The expression x if condition else y means Python checks the condition.

2. Step 2: Determine the returned value

   If condition is True, it returns x; if False, it returns y.

3. Final Answer:

   Returns x if condition is True, otherwise returns y. -> Option C

4. Quick Check:

   True condition = x, False condition = y [OK]

Hint: Remember: condition in middle, true value before else [OK]

Common Mistakes:

• Confusing the order of true and false values
• Thinking it always returns the first value
• Assuming it raises errors on false condition

2. Which of the following is the correct syntax for a ternary conditional expression in Python?

easy

A. condition ? x : y

B. if condition then x else y

C. x ? condition : y

D. x if condition else y

Solution

1. Step 1: Recall Python ternary syntax

   Python uses the format x if condition else y for ternary expressions.

2. Step 2: Compare options

   x if condition else y matches Python syntax exactly; others use syntax from other languages or incorrect forms.

3. Final Answer:

   x if condition else y -> Option D

4. Quick Check:

   Python ternary = x if condition else y [OK]

Hint: Python ternary always uses 'if' in the middle [OK]

Common Mistakes:

• Using ?: like in other languages
• Writing 'if condition then' which is invalid
• Swapping the order of parts

3. What is the output of this code?

age = 20
status = "Adult" if age >= 18 else "Minor"
print(status)

medium

A. Adult

B. Minor

C. True

D. False

Solution

1. Step 1: Evaluate the condition

   The condition age >= 18 is True because age is 20.

2. Step 2: Determine the value assigned

   Since condition is True, status is assigned "Adult".

3. Final Answer:

   Adult -> Option A

4. Quick Check:

   age 20 >= 18 is True, so status = Adult [OK]

Hint: Check condition result first, then pick value before else [OK]

Common Mistakes:

• Choosing the else value instead of the if value
• Confusing string output with boolean
• Ignoring the condition result

4. Find the error in this ternary expression:

result = "Pass" if score > 50 else "Fail" else "Invalid"

medium

A. SyntaxError due to multiple else keywords

B. No error, code runs fine

C. TypeError because of string comparison

D. NameError because score is undefined

Solution

1. Step 1: Analyze the ternary expression structure

   The expression has two else keywords, which is invalid syntax in Python ternary expressions.

2. Step 2: Understand Python ternary rules

   Python ternary expressions allow only one else part; multiple else cause SyntaxError.

3. Final Answer:

   SyntaxError due to multiple else keywords -> Option A

4. Quick Check:

   Only one else allowed in ternary [OK]

Hint: Only one else per ternary expression [OK]

Common Mistakes:

• Trying to chain else without nesting
• Assuming multiple else are allowed
• Ignoring syntax error messages

5. You want to create a dictionary where keys are numbers 1 to 5 and values are "Even" or "Odd" using a ternary expression inside a dictionary comprehension. Which code is correct?

hard

A. d = {x: "Even" if x % 2 == 0 "Odd" for x in range(1,6)}

B. d = {x: ("Even" if x % 2 == 0 else "Odd") for x in range(1,6)}

C. d = {x if x % 2 == 0 else "Odd": x for x in range(1,6)}

D. d = {x: "Even" else "Odd" if x % 2 == 0 for x in range(1,6)}

Solution

1. Step 1: Understand dictionary comprehension syntax

   It must be {key: value for variable in iterable}. The value can use a ternary expression.

2. Step 2: Check ternary expression placement

   d = {x: ("Even" if x % 2 == 0 else "Odd") for x in range(1,6)} correctly wraps the ternary expression in parentheses for clarity and correct parsing.

3. Step 3: Identify incorrect options

   d = {x: "Even" if x % 2 == 0 "Odd" for x in range(1,6)} misses the else keyword, causing SyntaxError; d = {x if x % 2 == 0 else "Odd": x for x in range(1,6)} misplaces ternary in key. d = {x: "Even" else "Odd" if x % 2 == 0 for x in range(1,6)} has invalid syntax.

4. Final Answer:

   d = {x: ("Even" if x % 2 == 0 else "Odd") for x in range(1,6)} -> Option B

5. Quick Check:

   Use parentheses around ternary in dict comprehension [OK]

Hint: Wrap ternary in parentheses inside dict comprehension [OK]

Common Mistakes:

• Placing ternary in key instead of value
• Missing parentheses causing syntax errors
• Using else before if in ternary