using switch, case and comparing strings

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Keith Holmlund
Keith Holmlund 2018-6-21
评论： belhassan haj mansour 2019-1-9
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 个评论
dpb
dpb 2018-6-21
编辑：dpb 2018-6-21
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 2018-6-21
编辑：Keith Holmlund 2018-6-21
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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采纳的回答

OCDER
OCDER 2018-6-21
编辑：OCDER 2018-6-21
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 个评论
显示 1更早的评论
OCDER
OCDER 2018-6-21
编辑：OCDER 2018-6-21
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 2018-6-21
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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更多回答（1 个）

belhassan haj mansour
编辑：belhassan haj mansour 2019-1-9
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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