Logical operators (&, |, ~) in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to perform element-wise AND operation between two logical arrays.

MATLAB

result = A [1] B;

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

A|

B&

C~

D&&

Attempts:

3 left

💡 Hint

Common Mistakes

Using | instead of & for AND operation.

Using && which only works for scalars, not arrays.

The & operator performs element-wise logical AND in MATLAB.

2fill in blank

medium

Complete the code to perform element-wise OR operation between two logical arrays.

MATLAB

result = A [1] B;

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

A|

B~

C&

D||

Attempts:

3 left

💡 Hint

Common Mistakes

Using & instead of | for OR operation.

Using || which only works for scalars, not arrays.

The | operator performs element-wise logical OR in MATLAB.

3fill in blank

hard

Fix the error in the code to correctly negate a logical array.

MATLAB

result = [1]A;

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

A^

B!

C~

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using ! which is not valid in MATLAB.

Using - or ^ which are arithmetic operators.

The ~ operator negates logical values element-wise in MATLAB.

4fill in blank

hard

Fill both blanks to create a logical expression that is true when A is true and B is false.

MATLAB

result = A [1] [2] B;

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

A&

B|

C~

D&&

Attempts:

3 left

💡 Hint

Common Mistakes

Using | instead of & for AND.

Not negating B correctly.

Use & for AND and ~ to negate B, so the expression is true only if A is true and B is false.

5fill in blank

hard

Fill all three blanks to create a logical expression that is true when either A or B is true, but not both.

MATLAB

result = (A [1] B) [2] ~ (A [3] B);

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

A&

B|

C~

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect operators that don't produce XOR behavior.

Misplacing negations.

This expression uses OR and AND with negations to create an XOR-like behavior: true if A or B is true, but not both.

Practice

1. Which logical operator in MATLAB returns true only if both conditions are true?

easy

A. ~ (NOT)

B. & (AND)

C. | (OR)

D. ^ (XOR)

Solution

1. Step 1: Understand the AND operator

   The & operator returns true only when both conditions it compares are true.

2. Step 2: Compare with other operators

   The | operator returns true if at least one condition is true, ~ negates a condition, and ^ is XOR which returns true if exactly one condition is true.

3. Final Answer:

   & (AND) -> Option B

4. Quick Check:

   Both true = true means AND = & [OK]

Hint: AND means both true, use & operator [OK]

Common Mistakes:

• Confusing & with | operator
• Thinking ~ returns true if both true
• Mixing XOR (^) with AND (&)

2. Which of the following is the correct syntax to negate a logical variable a in MATLAB?

easy

A. not a

B. !a

C. ~a

D. a~

Solution

1. Step 1: Recall MATLAB negation syntax

   In MATLAB, the negation operator is ~ placed before the variable to flip its logical value.

2. Step 2: Check each option

   not a uses 'not' which is not valid syntax, C uses '!' which is not MATLAB syntax, and D places '~' after the variable which is incorrect.

3. Final Answer:

   ~a -> Option C

4. Quick Check:

   Negate with ~ before variable [OK]

Hint: Use ~ before variable to negate in MATLAB [OK]

Common Mistakes:

• Using ! instead of ~ for negation
• Writing negation after variable
• Using 'not' keyword which is invalid

3. What is the output of the following MATLAB code?

a = true; b = false; c = a & ~b;

medium

A. true

B. false

C. 1

D. 0

Solution

1. Step 1: Evaluate ~b

   Since b is false, ~b is true.

2. Step 2: Evaluate a & ~b

   Both a and ~b are true, so a & ~b is true.

3. Final Answer:

   true -> Option A

4. Quick Check:

   true AND true = true [OK]

Hint: Negate false to true, then AND with true gives true [OK]

Common Mistakes:

• Confusing logical true/false with numeric 1/0
• Forgetting to negate b
• Assuming & acts like | (OR)

4. Identify the error in this MATLAB code snippet:

a = true;
b = false;
c = a | ~ b;

medium

A. No error, code runs correctly

B. Incorrect use of | operator

C. Extra space between ~ and b causes error

D. Missing parentheses around ~b

Solution

1. Step 1: Check operator usage

   The | operator is correctly used to perform logical OR between a and ~b.

2. Step 2: Check negation syntax

   The negation operator ~ can have a space before the variable; MATLAB ignores spaces here.

3. Final Answer:

   No error, code runs correctly -> Option A

4. Quick Check:

   Logical OR with negation syntax is valid [OK]

Hint: Spaces around ~ do not cause errors in MATLAB [OK]

Common Mistakes:

• Thinking ~ needs parentheses always
• Assuming space causes syntax error
• Confusing | with & operator

5. Given logical variables x = [true false true] and y = [false true true], what is the result of z = ~(x & y) | (x | y) in MATLAB?

hard

A. [false false false]

B. [false true true]

C. [true false true]

D. [true true true]

Solution

1. Step 1: Calculate x & y element-wise

   x = [true false true], y = [false true true]
   x & y = [true & false, false & true, true & true] = [false, false, true]

2. Step 2: Negate x & y

   ~(x & y) = [~false, ~false, ~true] = [true, true, false]

3. Step 3: Calculate x | y element-wise

   x | y = [true | false, false | true, true | true] = [true, true, true]

4. Step 4: Calculate final expression

   z = ~(x & y) | (x | y) = [true | true, true | true, false | true] = [true, true, true]

5. Final Answer:

   [true true true] -> Option D

6. Quick Check:

   Element-wise logic with ~, &, | gives all true [OK]

Hint: Calculate & first, then ~, then | element-wise [OK]

Common Mistakes:

• Forgetting element-wise operation
• Negating before AND instead of after
• Mixing up & and | precedence