inputparser: error when using a structure as a surrogate for parameter-value pairs.

I have a function that has a Required input, an Optional one and a Parameter-Value pair. I was trying to substitute the ParamValue pair with a structure, with StructExpand = true.

So let's say for example, if the function has

y = myfun(varargin)
p = inputParser;  
addRequired(p, 'a', @isnumeric);
addOptional(p, 'b', 1, @isscalar);
addParameter(p, 'c', 1, @isscalar);
parse(p, varargin{:})
...

If I call myfun(5, 'c', 2) there are no problems. But if I try to substitute myfun(5, 'c', 2) by defining st.c = 2 and then calling myfun(5, st), it gives me an error. The function works only if I specify also the Optional input and then the structure as in myfun(5, 1, st). Do you know why? Maybe the function reads st as 'b' input? How can I deal with this problem?

Thanks

Answer 1

[Ashish Gudla]

It would work when you define 'c' in a structure as well. Please see the example below:

function myfun(varargin)
p = inputParser;
p.StructExpand=1;
addRequired(p,'a',@isnumeric);
addOptional(p,'b',1,@isnumeric);
addParameter(p,'c',1,@isnumeric);
parse(p,varargin{:});
p.Results
end

>> myfun(5,'c',2)

ans =

    a: 5
    b: 1
    c: 2

>> st.c=2;

>> myfun(5,st)

ans =

    a: 5
    b: 1
    c: 2

What is the error you are getting? It may be unrelated to the issue you explained.