Error using == Matrix dimensions must agree.

Hi, I want a solution to this problem. Someone can help me?

Error in operations (line 5)
elseif c == 'multi'

Answer 1

[Star Strider]

I have no idea what the matrix dimension problem is, since we have only one line of your code. However, the way to compare strings and string variables is to use the strcmp or strcmpi functions.

So the correct syntax for the line you posted would be:

elseif strcmpi(c, 'multi')

[Alvaro Arenas]

Hi, Star Strider. Thank you for answer my question

I corrected the matlab code but now I have this problem

>> o1 = operations(4,'suma')

o1 =
     8

>> o2 = operations(4,'multi')
Error in operations (line 3)
if strcmpi(c, 'suma')

Output argument "o1" (and maybe others) not assigned during call to

[Star Strider]

The logic in your code is correct. I experimented with all the options.

You can realistically have only one output, not three, so I would change your code to:

function [out] = operations(M,c)
out = NaN;
if strcmpi(c, 'suma')
    out = M+M;
elseif strcmpi(c, 'multi')
    out = M*M;
elseif strcmpi(c, 'expo')
    out = M^M;
end
end

That should eliminate the error.

The initial assignment setting out to NaN covers the error condition when nothing matches ‘c’ correctly. The operation would not be defined, so that would actually be appropriate.

[Alvaro Arenas]

Star Strider Thank you so much. I resolved this problem

[Star Strider]

My pleasure.

If my Answer helped you resolve your problem, please Accept it.

[KenoKanawa]

Thank you, it solved my problem too !

[Star Strider]

@KenoKanawa — My pleasure!

[Dunzhi Chen]

Thanks, this solved my problem!

Answer 2

[Pronoy Das]

I came across a similar problem. Simply replace the single quotation marks with the double quotation marks, i.e. replace the line in your code with

c == "multi"