To run a function

I have a question in my mind. Why we need to put square bracket containing all output arguments ahead of the function when running a function in the command window? Instead of directly calling the function.

Why only by typing the full command with the output arguments appearing at the beginning can we get the result?

[John D'Errico]

Because that is how MATLAB syntax is defined? Software does what it is written to do, nothing more. MATLAB is just software.

[Joy Tian]

Well, you are right, John. Well I still like Matlab because it is so good at matrix.

Answer 1

[Thorsten]

You can call a function w/o the square brackets in front, but then you only get the first return value in ans, as David explained. If there is more than one return value, these are NOT assigned to, say, ans2, ans3, ..., probably because Mathworks decided not to clutter your workspace with unwanted data. Keep in mind that there are functions with many return values. So Matlab basically gives you only what you've asked for, with ans as an exception.

[Joy Tian]

I see. I will remember this.

Thank you Thorsten!

Answer 2

[David Young]

If you call the function without a result variable, MATLAB assigns the result to the variable ans. That is

min([3 2 1 5 6])

is the same in effect as

ans = min([3 2 1 5 6])

If you want to assign the result to some other variable, you can name it in front of the equals sign, with or without square brackets round it:

y = min([3 2 1 5 6])

or

[y] = min([3 2 1 5 6])

You only need the square brackets if the function can return more than one result. If you want the second result (and any later ones), you need to use the brackets and name the variables you want to assign the result to, like this:

[y, idx] = min([3 2 1 5 6])

[Joy Tian]

“You only need the square brackets if the function can return more than one result. If you want the second result (and any later ones), you need to use the brackets and name the variables you want to assign the result to”

That's it!

[y, idx] = min([3 2 1 5 6])

y =

     1

idx =

     3

Thank you so much, David!