Logical indexing in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select elements greater than 5 from the array.

MATLAB

A = [2, 7, 4, 9, 1];
result = A(A [1] 5);

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

A>

B<

C==

D~=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' will select elements less than 5.

Using '==' will select only elements equal to 5.

The operator '>' selects elements greater than 5 using logical indexing.

2fill in blank

medium

Complete the code to replace elements less than 3 with zero using logical indexing.

MATLAB

A = [1, 4, 2, 6, 3];
A(A [1] 3) = 0;

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

A<=

B>

C<

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' will select elements greater than 3, which is incorrect here.

Using '<=' will include elements equal to 3, which is not intended.

The operator '<' selects elements less than 3 to replace them with zero.

3fill in blank

hard

Fix the error in the code to select even numbers using logical indexing.

MATLAB

A = [1, 2, 3, 4, 5];
evenNums = A(mod(A, 2) [1] 0);

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

A==

B<

C>

D~=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '~=' selects odd numbers instead of even.

Using '>' or '<' does not correctly identify even numbers.

The '==' operator checks where the remainder is zero, selecting even numbers.

4fill in blank

hard

Fill both blanks to create a logical index for elements between 3 and 7 (inclusive).

MATLAB

A = [1, 4, 6, 8, 3];
idx = (A [1] 3) & (A [2] 7);

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

A>=

B<

C<=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' excludes 3, which is incorrect.

Using '<' excludes 7, which is incorrect.

Use '>=' for elements greater or equal to 3 and '<=' for elements less or equal to 7.

5fill in blank

hard

Fill all three blanks to create a dictionary of elements and their squares for elements greater than 2.

MATLAB

A = [1, 3, 5, 2];
result = containers.Map(A(A [1] 2), A(A [2] 2) [3] 2);

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

A>

B.*

C.^

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '.*' multiplies by 2 instead of squaring.

Using '+' adds 2 instead of squaring.

Select elements greater than 2 and map them to their squares using '.^ 2'.