HOW TO CHECK THE PARAMETERS RECEIVED IN THE FUNCTION CALL?

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federica pasquali 2018-8-2

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评论： OCDER 2018-8-9

dear all,

this is my function : function [] = print( value1 , value2, value3 ,value4,value5,value6,value7,value8)

value1 and value 2 are REQUIRED the others are OPTIONAL . I need to know how to check which parameters i've received and their value , because some of them could be numbers , characters . and i don't know how to do that. thanks

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Answer 1

OCDER 2018-8-2

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I think input parser + varargin is what you need here.

Example:

%Changed the name "print" to "print2" to prevent overriding matlab built-in "print" function
function [] = print2(varargin)  
P = inputParser;
addRequired(P, 'value1', @ischar);
addRequired(P, 'value2', @isnumeric);
addOptional(P, 'value3', [], @(x) ischar(x) || isnumeric(x));
parse(P, varargin{:});
P = P.Results; %Just so you can refer to value1 as P.value1, not P.Results.value1 (downside to inputParser)
%To get value1, use P.value1

Alternatively, you'll have to make your own input-parsing function

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OCDER 2018-8-3

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The mainthing you can do with inputParser is to make sure the user inputs the correct things. You can check if user input a correct value for "Ch" for example via something like this:

addOptional(P, 'Ch', 'A', @(x) ischar(x) && any(strcmpi(x, {'A', 'B', 'C', 'D'})))

If you want to take different courses of action depending on the input, then you need a separate step AFTER input parsing, as I've show via the switch.

parse the user inputs - make sure they are valid inputs
use switch statements to decide what to do for each condition
run your main computation based on the input and parameters set for the input

Or did I misunderstood?

OR, maybe it's better if you use name-value input parsing, where the user should specifically tell what values they are giving the function.

addParameter(P, 'Ch', 'A', ...)

With this option, user must give name-value ('Ch', 'A') pairs to the function:

myFunction(V1, V2, 'Ch', 'A')

That way, you know that the user DID give a value for 'Ch'. Otherwise, having to determine what users did/did not provide will push a lot of input parsing work to you. You'll have to go the custom input parsing route and do a lot of checks via "if" statements.

OCDER 2018-8-6

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If you want variable types of inputs like

   prova('1a',folder,'b')
   prova('1a',folder,30,40,60)

then you'll have to make more input parsing checks + custom checking.

function [] = prova(ID , Folder , varargin) 
 if nargin > 3 & strcmpi(varargin{1}, {'b', 'r', ...'})
    Chain = varargin{1};
    varargin = varargin(2:end);
else
    Chain = '';
end
P = inputParser; 
addRequired( P , 'ID' ); 
addRequired( P , 'Folder' );
%%addOptional( P , 'Chain' , '' , @(x) ischar(x) ); %%DELETE. You did the parsing earlier, separately, as it's special
addOptional( P , 'X' , [] , @(x) isnumeric(x) );
addOptional( P , 'Y' ,[] , @(x) isnumeric(x) ); 
addOptional( P , 'Z' ,[] , @(x) isnumeric(x) ); 
addOptional( P , 'Display' ,'', @(x) ischar(x) ); 
addOptional( P , 'Color' ,'' , @(x) ischar(x) ); 
parse(P , ID , Folder , varargin {:}); 
P = P.Results

The other option, if you want a "cleaner" version, is to make sure Display, Color, and Chain are "addParameter" options

%prova('1a',folder, 'Chain', 'b')
%prova('1a',folder,X, Y, Z, 'Display', 'none', 'Chain', 'b', 'Color', 'r')
function Out = prova(ID, Folder, varargin)
P = inputParser; 
addRequired( P , 'ID' ); 
addRequired( P , 'Folder' );
addOptional( P , 'X' , [] , @(x) isnumeric(x) );
addOptional( P , 'Y' ,[] , @(x) isnumeric(x) ); 
addOptional( P , 'Z' ,[] , @(x) isnumeric(x) ); 
addParameter( P , 'Chain' , '' , @(x) ischar(x) ); %<-- addParameter
addParameter( P , 'Display' ,'', @(x) ischar(x) ); %<-- addParameter
addParameter( P , 'Color' ,'' , @(x) ischar(x) ); %<-- addParameter
parse(P , ID , Folder , varargin {:}); 
P = P.Results

federica pasquali 2018-8-9

I really want to thank you for the help. you were very kind

OCDER 2018-8-9

You're welcome!

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Answer 2

federica pasquali 2018-8-5

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在 MATLAB Online 中打开

function [] = prova(ID , Folder , varargin) 
P = inputParser; 
addRequired( P , 'ID' ); 
addRequired( P , 'Folder' ); 
addOptional( P , 'Chain' , '' , @(x) ischar(x) );
addOptional( P , 'X' , [] , @(x) isnumeric(x) );
addOptional( P , 'Y' ,[] , @(x) isnumeric(x) ); 
addOptional( P , 'Z' ,[] , @(x) isnumeric(x) ); 
addOptional( P , 'Display' ,'', @(x) ischar(x) ); 
addOptional( P , 'Color' ,'' , @(x) ischar(x) ); 
parse(P , ID , Folder , varargin {:}); 
P = P.Results
end

if i'm calling prova('1a',folder,'b') it's going to work. but if i'm calling prova('1a',folder,30,40,60) without chain (before ='b') doesn't work , i received this error :The value of 'Chain' is invalid. It must satisfy the function: @(x)ischar(x). so i've tried to use try catch like this

try 
  addOptional( P , 'Chain' , '' , @(x) ischar(x) ); 
 catch ME 
end
but it doesn't work and i don't know how ho to built a ME object .

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