Comparison operators in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if variable a is equal to 10.

MATLAB

result = (a [1] 10);

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

A==

B=

C~=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' instead of '==' for comparison.

Using '~=' which means not equal.

In MATLAB, == is used to compare if two values are equal.

2fill in blank

medium

Complete the code to check if variable x is greater than 5.

MATLAB

if x [1] 5
    disp('x is greater than 5');
end

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

A>

B==

C<=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' which means less than.

Using '==' which means equal.

The operator > checks if the left value is greater than the right value.

3fill in blank

hard

Fix the error in the code to check if y is not equal to 0.

MATLAB

if y [1] 0
    disp('y is not zero');
end

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

A=

B==

C~=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' instead of '~='.

Using '==' which means equal.

The operator ~= means 'not equal' in MATLAB.

4fill in blank

hard

Fill both blanks to create a logical expression that checks if z is between 1 and 10 (inclusive).

MATLAB

if (z [1] 1) && (z [2] 10)
    disp('z is between 1 and 10');
end

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

A>=

B<

C<=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' instead of '>=' for the lower bound.

Using '<' instead of '<=' for the upper bound.

Use >= to check if z is at least 1, and <= to check if z is at most 10.

5fill in blank

hard

Fill all three blanks to create a dictionary (struct) comprehension that stores whether each number in nums is less than 5.

MATLAB

result = struct();
for i = 1:length(nums)
    result.[1] = (nums(i) [2] 5);
end
keys = fieldnames(result);
for k = 1:length(keys)
    disp([keys{k} ': ' num2str(result.(keys{k}))]);
end

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

Anum2str(i)

B<

Cnum2str(nums(i))

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using numbers directly as field names.

Using '>' instead of '<' for comparison.

We use num2str(nums(i)) as the field name, check if nums(i) < 5, and convert i to string for display.

Practice

1. What does the MATLAB expression 5 > 3 return?

easy

A. 0 (false)

B. 1 (true)

C. Error

D. 5

Solution

1. Step 1: Understand the comparison operator

   The operator > checks if the left value is greater than the right value.

2. Step 2: Compare the values 5 and 3

   Since 5 is greater than 3, the expression returns true, which is represented as 1 in MATLAB.

3. Final Answer:

   1 (true) -> Option B

4. Quick Check:

   5 > 3 = 1 [OK]

Hint: Greater than means left number bigger than right [OK]

Common Mistakes:

• Confusing true (1) with false (0)
• Thinking it returns the bigger number
• Using wrong operator like < instead of >

2. Which of the following is the correct MATLAB syntax to check if variable a is equal to 10?

easy

A. a = 10

B. a === 10

C. a != 10

D. a == 10

Solution

1. Step 1: Identify the equality operator in MATLAB

   MATLAB uses double equal signs == to test equality, not a single equal sign.

2. Step 2: Check each option

   a = 10 assigns 10 to a, not compare. a == 10 correctly compares a to 10. a === 10 uses triple equals which is invalid in MATLAB. a != 10 uses not equal operator incorrectly.

3. Final Answer:

   a == 10 -> Option D

4. Quick Check:

   Equality test uses == [OK]

Hint: Use double equals (==) to compare, single equals (=) assigns [OK]

Common Mistakes:

• Using single = instead of ==
• Using === which is not MATLAB syntax
• Confusing != with ~= for not equal

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

a = [1 3 5]; b = [2 3 4]; result = a <= b;

medium

A. [1 1 0]

B. [1 0 0]

C. [0 1 1]

D. [0 0 1]

Solution

1. Step 1: Understand element-wise comparison

   The operator <= compares each element of a with the corresponding element of b.

2. Step 2: Compare each pair

   1 <= 2 is true (1), 3 <= 3 is true (1), 5 <= 4 is false (0).

3. Final Answer:

   [1 1 0] -> Option A

4. Quick Check:

   Element-wise <= comparison = [1 1 0] [OK]

Hint: Compare arrays element-wise for <= operator [OK]

Common Mistakes:

• Thinking it returns a single value
• Mixing up < and <= operators
• Forgetting element-wise comparison

4. Identify the error in this MATLAB code snippet:

if a = 5
    disp('Equal');
end

medium

A. Missing semicolon after assignment

B. disp function is incorrect

C. Using = instead of == in if condition

D. if statement needs parentheses

Solution

1. Step 1: Check the if condition syntax

   In MATLAB, the if condition requires a logical expression, not an assignment.

2. Step 2: Identify the operator mistake

   The code uses = which assigns 5 to a, instead of == which compares a to 5.

3. Final Answer:

   Using = instead of == in if condition -> Option C

4. Quick Check:

   Comparison uses ==, not = in conditions [OK]

Hint: Use == for comparison inside if, not = [OK]

Common Mistakes:

• Using = instead of ==
• Adding unnecessary parentheses
• Misusing disp function

5. Given two arrays A = [4 7 2 9] and B = [5 7 3 8], write a MATLAB expression using comparison operators to create a logical array that is true where elements of A are greater than or equal to B and false otherwise. What is the resulting array?

hard

A. [0 1 0 1]

B. [1 1 1 1]

C. [0 0 0 0]

D. [1 0 1 0]

Solution

1. Step 1: Use element-wise comparison operator

   Use the operator >= to compare each element of A with B element-wise.

2. Step 2: Compare each element pair

   4 >= 5 is false (0), 7 >= 7 is true (1), 2 >= 3 is false (0), 9 >= 8 is true (1).

3. Final Answer:

   [0 1 0 1] -> Option A

4. Quick Check:

   A >= B = [0 1 0 1] [OK]

Hint: Use >= for element-wise greater or equal comparison [OK]

Common Mistakes:

• Using > instead of >=
• Confusing logical array with numeric values
• Mixing element-wise with matrix operations