using switch, case and comparing strings

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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
  2 Comments
dpb
dpb on 21 Jun 2018
Edited: dpb on 21 Jun 2018
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
Keith Holmlund on 21 Jun 2018
Edited: Keith Holmlund on 21 Jun 2018
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

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Accepted Answer

OCDER
OCDER on 21 Jun 2018
Edited: OCDER on 21 Jun 2018
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.
  3 Comments
OCDER
OCDER on 21 Jun 2018
Edited: OCDER on 21 Jun 2018
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
Walter Roberson on 21 Jun 2018
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.

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More Answers (1)

belhassan haj mansour
belhassan haj mansour on 9 Jan 2019
Edited: belhassan haj mansour on 9 Jan 2019
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 ?

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