Logical operators in conditions in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of combined logical operators

What is the output of this Python code snippet?

Python

x = 5
if x > 3 and not x == 5:
    print("A")
elif x > 3 or x == 5:
    print("B")
else:
    print("C")

A B

B SyntaxError

C C

D A

💡 Hint

Remember how 'and', 'or', and 'not' work together in conditions.

The first condition checks if x > 3 and x is not 5. Since x is 5, 'not x == 5' is False, so the first if fails. The elif checks if x > 3 or x == 5, which is True, so it prints 'B'.

❓ Predict Output

intermediate

Evaluating multiple logical conditions

What will be printed by this code?

Python

a = True
b = False
c = True
if a and b or c:
    print("Yes")
else:
    print("No")

A RuntimeError

B No

C SyntaxError

D Yes

💡 Hint

Remember the precedence of 'and' over 'or'.

The expression 'a and b or c' is evaluated as '(a and b) or c'. Since a and b is False, but c is True, the overall condition is True, so it prints 'Yes'.

❓ Predict Output

advanced

Output with mixed logical operators and parentheses

What is the output of this code?

Python

x = 10
if (x < 5 or x > 8) and not (x == 10):
    print("First")
elif x == 10 and not (x < 5):
    print("Second")
else:
    print("Third")

A First

B Second

C Third

D SyntaxError

💡 Hint

Check each condition carefully with parentheses.

The first if condition is False because although (x < 5 or x > 8) is True, 'not (x == 10)' is False. The elif condition is True because x == 10 and not (x < 5) is True, so it prints 'Second'.

❓ Predict Output

advanced

Logical operators with short-circuit behavior

What will this code print?

Python

def check():
    print("Checked")
    return False

if False and check():
    print("Yes")
else:
    print("No")

A No

B

Checked
Yes

C

Checked
No

D SyntaxError

💡 Hint

Remember how 'and' stops evaluating if the first part is False.

Because the first part of 'and' is False, Python does not call check(), so 'Checked' is not printed. The else block runs and prints 'No'.

❓ Predict Output

expert

Complex logical condition output

What is the output of this code?

Python

x = 3
y = 4
z = 5
if (x > y or y < z) and not (x == 3 and z == 5):
    print("Alpha")
elif x == 3 and (y == 4 or z == 6):
    print("Beta")
else:
    print("Gamma")

A Alpha

B Gamma

C Beta

D SyntaxError

💡 Hint

Evaluate each part step by step, especially the 'not' condition.

The first if condition is False because although (x > y or y < z) is True, the 'not (x == 3 and z == 5)' is False (since x==3 and z==5 is True). The elif condition is True because x==3 and (y==4 or z==6) is True, so it prints 'Beta'.

Practice

1. Which logical operator in Python means all conditions must be true for the whole expression to be true?

easy

A. xor

B. and

C. not

D. or

Solution

1. Step 1: Understand the meaning of 'and'

   The and operator returns true only if both conditions are true.

2. Step 2: Compare with other operators

   or needs only one true condition, not reverses truth, and xor is not a Python keyword.

3. Final Answer:

   and -> Option B

4. Quick Check:

   All conditions true = and [OK]

Hint: Remember: 'and' means all must be true [OK]

Common Mistakes:

• Confusing 'and' with 'or'
• Thinking 'not' means all true
• Using 'xor' which is not a Python keyword

2. Which of the following is the correct syntax to check if variable x is NOT equal to 10 and variable y is greater than 5?

easy

A. if x != 10 and y > 5:

B. if x <> 10 and y > 5:

C. if x != 10 & y > 5:

D. if x != 10 or y > 5:

Solution

1. Step 1: Check the inequality operator

   != is the correct 'not equal' operator in Python; <> is invalid syntax.

2. Step 2: Check logical operator usage

   and correctly combines two conditions; & is a bitwise operator and or changes logic.

3. Final Answer:

   if x != 10 and y > 5: -> Option A

4. Quick Check:

   Correct inequality and 'and' syntax [OK]

Hint: Use '!=' for not equal and 'and' to combine conditions [OK]

Common Mistakes:

• Using '<>' instead of '!='
• Using '&' instead of 'and'
• Using 'or' when 'and' is needed

3. What will be the output of this code?

age = 20
has_id = False
if age >= 18 and has_id:
    print('Allowed')
else:
    print('Denied')

medium

A. SyntaxError

B. Allowed

C. Denied

D. No output

Solution

1. Step 1: Evaluate each condition

   age >= 18 is True since 20 >= 18, but has_id is False.

2. Step 2: Apply 'and' operator

   True and False is False, so the else block runs.

3. Final Answer:

   Denied -> Option C

4. Quick Check:

   True and False = False [OK]

Hint: Both conditions must be true for 'and' to print Allowed [OK]

Common Mistakes:

• Assuming one True is enough with 'and'
• Confusing 'and' with 'or'
• Ignoring boolean value of variables

4. Find the error in this code snippet:

if not x > 10 or y < 5
    print('Check passed')

medium

A. Missing colon ':' after condition

B. Wrong use of 'not' operator

C. Incorrect indentation

D. Using 'or' instead of 'and'

Solution

1. Step 1: Check syntax of if statement

   Python requires a colon ':' at the end of the if condition line.

2. Step 2: Review other parts

   The use of not and or is correct; indentation is not shown as wrong here.

3. Final Answer:

   Missing colon ':' after condition -> Option A

4. Quick Check:

   if statements need ':' [OK]

Hint: Always put ':' after if condition [OK]

Common Mistakes:

• Forgetting ':' after if
• Misusing 'not' operator
• Wrong indentation without colon

5. You want to check if a number n is either less than 0 or greater than 100, but NOT equal to -10. Which condition correctly uses logical operators?

hard

A. if n < 0 or (n > 100 and n != -10):

B. if n < 0 and n > 100 or n != -10:

C. if not (n < 0 or n > 100) and n == -10:

D. if (n < 0 or n > 100) and n != -10:

Solution

1. Step 1: Understand the condition requirements

   We want numbers less than 0 or greater than 100, but exclude -10.

2. Step 2: Analyze each option

   if (n < 0 or n > 100) and n != -10: correctly groups the or condition and excludes -10 with and n != -10. if n < 0 or (n > 100 and n != -10): excludes -10 only when >100, not <0 (e.g., n=-10 is true). if not (n < 0 or n > 100) and n == -10: reverses logic and checks for equal -10. if n < 0 and n > 100 or n != -10: mixes and/or incorrectly.

3. Final Answer:

   if (n < 0 or n > 100) and n != -10: -> Option D

4. Quick Check:

   Group or, then exclude -10 with and [OK]

Hint: Group or conditions, then exclude with and [OK]

Common Mistakes:

• Wrong grouping of conditions
• Misplacing 'not' or 'and'
• Confusing '!=' with '=='