FREE MATLAB Data Types and Structures Questions and Answers

Question 1

An engineer needs to store data for multiple electronic components.
Each component has a text-based part number (e.g., 'R-101'), a numeric resistance value (e.g., 4700), and a 1x2 vector for its physical dimensions (e.g., [0.25, 0.125]).
Which data structure is most suitable for creating an array to hold all the information for 50 such components?

Accepted Answer

A structure array

Answer

A cell array

Answer

A multidimensional numeric array

Answer

A table with mixed data types

Question 2

A data analyst has a list of experimental conditions stored in a string array: `conditions = ["Low", "Medium", "High", "Medium", "Low"];`. To improve memory efficiency and enable mathematical comparisons (e.g., 'Low' < 'Medium'), which data type conversion is most appropriate?

Accepted Answer

Convert to an ordinal `categorical` array

Answer

Convert to a numeric array using `double()`

Answer

Convert to a cell array of character vectors

Answer

Convert to a `table` with one variable

Question 3

A programmer creates two text variables as follows:
`text1 = 'Results';`
`text2 = "Results";`

What are the data types (classes) of `text1` and `text2` respectively?

Accepted Answer

`char` and `string`

Answer

`string` and `char`

Answer

Both are `char`

Answer

Both are `string`

Question 4

A programmer needs to create a single container variable that can hold the following three items: a 4x4 magic square, the character vector 'Experiment A', and a `datetime` object. Which of the following commands correctly creates such a container?

Accepted Answer

C = {magic(4), 'Experiment A', datetime('now')}

Answer

C = [magic(4); 'Experiment A'; datetime('now')]

Answer

C = struct('Data', magic(4), 'Name', 'Experiment A', 'Time', datetime('now'))

Answer

C = table(magic(4), 'Experiment A', datetime('now'))

Question 5

Given a table `T` created with the command `T = table([8; 10; 11], ["A"; "B"; "B"], 'VariableNames', {'Score', 'Group'})`. Which command correctly extracts the 'Score' value from the row where 'Group' is equal to "A"?

Accepted Answer

T.Score(T.Group == "A")

Answer

T('A', 'Score')

Answer

T{T.Group("A"), 'Score'}

Answer

T(1, 1)

Question 6

A financial analyst has two `datetime` objects: `d1 = datetime('2025-01-10');` and `d2 = datetime('2025-03-15');`. To find the total number of calendar days that have passed between these two dates, which is the most direct command?

Accepted Answer

d2 - d1

Answer

days(d2 - d1)

Answer

caldays(d2 - d1)

Answer

between(d1, d2)