I get Error: Invalid expression. Check for missing or extra characters. when commenting out lines in a multi-line statement

It seems you can't comment-out entire lines in MATLAB within a multi-line statement. Or am I doing it wrong.

A few examples below.

1. Expressions

y = ...
1 + ...
2 + ...
3

Returns:

y =

6

y = ...
1 + ...
%2 + ...
3

Raises:

%2 + ...

↑

Error: Invalid expression. Check for missing or extra characters.

2. Structure definitions

s = struct(...
    'A',1,...
    'B',2,...
    'C',3....
)

Returns:

s =

struct with fields:

A: 1

B: 2

C: 3

struct(...
    'A',1,...
%    'B',2,...
    'C',3...
)

Raises:

% 'B',2,...

↑

Error: Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched

delimiters.

Even if I use the Comment tool () in the MATLAB editor it causes these errors.

This is such a basic task! What am I doing wrong?

Answer 1

[madhan ravi]

You're right.

[madhan ravi]

It expects anything (in a MATLAB sense) other than a comment.

https://www.mathworks.com/help/matlab/matlab_prog/continue-long-statements-on-multiple-lines.html

dot dot dot or ellipsis

[Bill Tubbs]

I wonder whether the ellipsis is even necessary within parenthesis. Python uses '\' for line continuation (ellipsis is used for other things) but it may be omitted within parenthesis:

y = (
    1
    + 2
    + 3
)

Anyhow, I'm getting off topic...

Answer 2

[Bill Tubbs]

Here is one solution but it's hardly very convenient and contrary to commenting-out in other languages:

y = ...
1 + ...
...%2 + ...
3

Returns:

y =

4

s = struct(...
    'A',1,...
...%     'B',2,...
    'C',3....
)

Returns:

s =

struct with fields:

A: 1

C: 3

[madhan ravi]

It is the same as

y = ...
1 + ...
... 2 + ... 
3

Which does exactly as the document says that I linked in my answer.

[Bill Tubbs]

This is the best solution I think. Don't use '%' at all, just precede any lines you want to comment out with '...'.