MATLAB tutorials:MATLAB Fundamentals may have a wrong answer

Visualizing Data in 2D and 3D > Customized Annotations > (3/3) Adding Specialized Annotations

Task 2

The offical answer is

ylabel(yTxt)

But I think the right answer is

clear ylabel
ylabel(yTxt)

Although I think "clear ylabel" should not be necessary.

Answer 1

[Hiro Yoshino]

I do not think you are right.

ylabel (find the link here) is not a variable but a command. So you do not need to clear it unless you have a variable named "ylabel".

last = 4;
r = 0:0.1:last;
A = pi*r.^2;
plot(r,A)
xlabel("r");
yTxt = ["Area";"\pi r^2"];
ylabel("Hello");

[XIAO]

I am so sorry. You are right, and I might do some wrong operations to get this wrong conslusion.

[DGM]

You will find that a number of answers on the topic do mention clearing ylabel or xlabel.

The reason is simply that it's very common that users accidentally create a variable by the same name and then wonder why xlabel() and ylabel() don't work. When that happens, one has to clear the variable in order to use the function of the same name.

https://www.mathworks.com/matlabcentral/answers/29677-index-exceeds-matrix-dimensions#answer_355791

Just like size(), image() and title(), xlabel() is one of many functions with a name that makes a very obvious and convenient variable name. These things happen.