MATLAB Variables and Workspace Interaction 2

Question 1

Which command removes ALL variables from the MATLAB workspace without prompting for confirmation?

Accepted Answer

clear

Answer

`clear` (with no arguments) removes all variables from the current workspace silently.

Question 2

What does the `whos` command display that `who` does not?

Accepted Answer

Size, bytes, and class of each variable

Answer

`whos` provides detailed information including size, allocated bytes, and data class, while `who` lists only variable names.

Question 3

After executing `x = 5; y = x; x = 10;`, what is the value of `y`?

Accepted Answer

5

Answer

MATLAB uses value semantics for numeric types, so `y` receives a copy of `x` at the time of assignment and is unaffected by later changes to `x`.

Question 4

Which function checks whether a variable named 'myVar' exists in the current workspace?

Accepted Answer

exist('myVar', 'var')

Answer

`exist('myVar', 'var')` returns 1 if `myVar` is defined in the current workspace and 0 otherwise.

Question 5

What is the result of assigning `A = [1 2; 3 4]; B = A;` and then modifying `B(1,1) = 99;`?

Accepted Answer

A remains [1 2; 3 4]

Answer

MATLAB uses copy-on-write semantics, so modifying `B` creates a separate copy, leaving `A` unchanged.

MATLAB - MATLAB Technical Computing Practice Test