Invalid array indexing before arguing variable

For example,

sheetnames(FullFilePath)

This will give me string array (e.g., 5x1).

So, I tried to access directly one of elements like below

sheetnames(FullFilePath)(1)

But, this did not work.

A = sheetnames(FullFilePath)
A(1)

However, after arguing variable, if I do the same approach, then I could access the element.

Why does this happen? what is the difference between first and second approach.

I thought both looks the same.

[Walter Roberson]

sheetnames is defined as as a function returning a string array.

You cannot directly use () or {} indexing on the return value from a function, so

sheetnames(FullFilePath)(1)

is invalid as that is trying to do () indexing on the return value of a function.

The only kind of indexing that you can do on the return value from a function is dot indexing

This is a limitation on the MATLAB parser .

There is some history behind it. Consider for example,

ones(2)

If you were permitted to directly index the result of a function call, you would not be able to tell whether ones(2) is a call to function ones with parameter 2, or if it is instead a call to function ones with no parameters, with the result to be indexed at (2) .

[the cyclist]

Coincidentally, @Walter Roberson, I just happened to be looking at your answer to the What is Missing from MATLAB? thread today. (That page takes forever to load now.)

[Hokon]

@Walter Roberson I see. Thanks for your reply. Now it's clear to me. I'm curious about this.

Answer 1

[Hokon]

Above comment gave me answers.