name value pairs with variable input arguments

function db = name_value_pairs(varargin)
n=length(varargin); db ={};
if mod(n,2)~=0 || n ==0 
    db= {};
elseif ~ischar(varargin(1:2:nargin))
   
        db = {};
else

    for i=1:2:n
    db(i)=[db; varargin{i} varargin{i+1}]
    end
end
end
%this is code that i have written and ii cant understand why it result
%  db =

  %  0×0 empty cell array

Answer 1

[Benjamin Kraus]

The problem is:

~ischar(varargin(1:2:nargin))

The varargin input will always be a cell-array, so this condition will never be true.

I think what you want is:

~iscellstr(varargin(1:2:nargin))

This will verify that the input is a cell-array whose elements are all character vectors.

But, putting any issues in the code aside, unless I'm missing something, your entire function can be written like this:

function db = name_value_pairs(varargin)
if mod(nargin,2)~=0 || ~iscellstr(varargin(1:2:nargin))
    db = {};
else
    db = varargin;
end

In addition, unless you require the added validation, your function can be replaced in your code by just wrapping your inputs in curly braces.

db = name_value_pairs('a',10,'b',20);
db2 = {'a',10,'b',20};
% db and db2 will be the same