using switch, case and comparing strings

I am using a function with varargin that imports strings and numbers but the first input is always a string. based off what it says, using switch and case, I want the function to do something different. So if for example, str = char(varargin{1}) = 'hot dog' and I had

switch str

case str == 'hot dog'

case str == 'burger'

When I do this I get an error, what am I doing wrong

[dpb]

str = varargin{1} = 'hot dog'

is illegal syntax and the SWITCH construct is missing any action statements in the cases plus isn't closed.

A properly formed SWITCH construct will work just fine with string or character variables; it will have an issue with a cellstr() argument unless you take care to dereference it.

We need to see the actual function to debug, not just bits and pieces.

[Keith Holmlund]

It looks something like this, The first input is 'hot dog'. When run I enter Menu('hot dog','ketchup'). I am getting an error at the first case line

 function Menu(varargin)

 cat = char(varargin{1});
 switch cat
       case cat == 'hot dog'
            condiment = char(varargin{2});
            subfunction
       case cat == 'burger'
            bun = char(varargin{2});
            subfunction2
 end

Answer 1

[OCDER]

The switch statement is used incorrectly. Remove the "str ==" after case.

function Menu(varargin)

%varargin = {'hot dog', 1, 2, 3};
str = varargin{1};
switch lower(str) %make it case insensitive. all lower cases
    case 'hot dog'
        disp('Delicious hot dogs!')
    case 'burger'
        disp('Mouth-watering burgers!')
end

Actually, what was the Error message? I should have waited for your response to @dpb since there are multiple issues, as already pointed out.

[Keith Holmlund]

Error using == Comparison between logical and string is not supported.

[OCDER]

Remove 'cat == ' after your case. And DO NOT use "cat" as a variable, as that's a built-in matlab function for concatenate arrays.

help cat

I like to label my variables with 1st letter caps, just in case I accidentally name a variable the same as a matlab function.

[Walter Roberson]

I tested with OCDER's code, and it looks fine to me.

OCDER's code does not use any string data types and so could not get that message.

Answer 2

[belhassan haj mansour]

HELLO

im trying to control a rocker switch with another one in app designer, for example i have rockerswitch1 in the position 'off' and rockerswitch2 also in position 'off' . what i need is when i put rockerswitch1 in position 'on', the rockerswitch 2 become in the position 'on' too but i can't find the right function to do so

CAN ANYONE HELP ME WITH THIS PLEASE ?

[Walter Roberson]

Please create a new Question for this .

[belhassan haj mansour]

done