Thread Subject: Combining/Overwriting structs

Hallo!

  I'm setting up some default options with a struct:
defaults.color = 'r';
defaults.marker = 'o';
defaults.text = false;

  A user can now change some of the default option. e.g.:
options.color = 'k';

  Now I'd like to overwrite the default options with the options changed by the user:
finaloptions = Overwrite(defaults, options)

  Giving:
finaloptions.color = 'k';
finaloptions.marker = 'o';
finaloptions.text = false;

  Is there a function that does this for me or do I have to program it myself?

Thanks,
  Ralph

On Mar 11, 2:09 pm, "Ralph " <news2...@ecuapac.dyndns.org> wrote:
> Hallo!
>
>   I'm setting up some default options with a struct:
> defaults.color = 'r';
> defaults.marker = 'o';
> defaults.text = false;
>
>   A user can now change some of the default option. e.g.:
> options.color = 'k';
>
>   Now I'd like to overwrite the default options with the options changed by the user:
> finaloptions = Overwrite(defaults, options)
>
>   Giving:
> finaloptions.color = 'k';
> finaloptions.marker = 'o';
> finaloptions.text = false;
>
>   Is there a function that does this for me or do I have to program it myself?
>
> Thanks,
>   Ralph

why not initialize options.color to defaults.color
then set
finaloptions.color=options.color
?

http://www.eecs.umich.edu/~fessler/irt/irt/utilities/vararg_pair.m

jason <jason.mellone@gmail.com> wrote in message <1573bdf5-
> why not initialize options.color to defaults.color
> then set
> finaloptions.color=options.color
> ?

Because the only thing the user should need to do is to setup those option they want to change.

Yes, I could give them the defaults-structure but I don't want to. And yes, it's only cosmetics, I know.

Ralph

In article <hnbf4i$4ao$1@fred.mathworks.com>, news2008
@ecuapac.dyndns.org says...
> Hallo!
>
> I'm setting up some default options with a struct:
> defaults.color = 'r';
> defaults.marker = 'o';
> defaults.text = false;
>
> A user can now change some of the default option. e.g.:
> options.color = 'k';
>
> Now I'd like to overwrite the default options with the options changed by the user:
> finaloptions = Overwrite(defaults, options)
>
> Giving:
> finaloptions.color = 'k';
> finaloptions.marker = 'o';
> finaloptions.text = false;
>
> Is there a function that does this for me or do I have to program it myself?
>
> Thanks,
> Ralph
>

You might find some good ideas in these 2 posts:

http://blogs.mathworks.com/loren/2009/05/05/nice-way-to-set-function-
defaults/

http://blogs.mathworks.com/loren/2009/05/12/optional-arguments-using-
empty-as-placeholder/

--
Loren
http://blogs.mathworks.com/loren
http://matlabwiki.mathworks.com/MATLAB_FAQ

"Matt J " <mattjacREMOVE@THISieee.spam> wrote in message <hnbfsu$nq8$1@fred.mathworks.com>...
>
>
> http://www.eecs.umich.edu/~fessler/irt/irt/utilities/vararg_pair.m

Incidentally, the above file requires that you pass the options as string-value pairs. Below is a wrapper that I routinely use, which will allow you to pass options in structure form as well.


function [varargout]=optionproc(default, options, varargin)
%Process options encapsulated as either a structure or as a cell array
%
%[optionstruct,extras]=optionproc(default, options, varargin)
%
% default: structure of default values
% options: a structure whose fields are given values or a cell array
% of the form {'Option1',Option1,'Option2',Option2,...}
%
% varargin: arguments to be passed to vararg_pair.m


nn=length(options);

if nn==0
    
    optionstruct=default;
    varargout{1}=default;
    varargout{2}={};
    return
    
elseif iseven(nn)
    
    varargs=options;
    
elseif nn==1 %structure input mode
    
  if iscell(options),
     options=options{1};
  end
  
  if ~isstruct(options), error 'Attempted structure mode input?'; end
  
  varargs=[fieldnames(options),struct2cell(options)]';
  varargs=varargs(:)';
    
else
    error 'Unrecognized Input'
end


varargout=cell(1,nargout);
[varargout{:}]=vararg_pair(default,varargs,varargin{:});

"Ralph " <news2008@ecuapac.dyndns.org> wrote in message <hnbf4i$4ao$1@fred.mathworks.com>...
> Hallo!
>
> I'm setting up some default options with a struct:
> defaults.color = 'r';
> defaults.marker = 'o';
> defaults.text = false;
>
> A user can now change some of the default option. e.g.:
> options.color = 'k';
>
> Now I'd like to overwrite the default options with the options changed by the user:
> finaloptions = Overwrite(defaults, options)
>
> Giving:
> finaloptions.color = 'k';
> finaloptions.marker = 'o';
> finaloptions.text = false;
>
> Is there a function that does this for me or do I have to program it myself?
>
Yup, there is catstruct.m to be found on the file exchange:
http://www.mathworks.com/matlabcentral/fileexchange/7842-catstruct

HTH.
Bjoern

"Bjorn Gustavsson" <bjonr@irf.se> wrote in message <hnbkuo$o5a$1@fred.mathworks.com>...

> Yup, there is catstruct.m to be found on the file exchange:
> http://www.mathworks.com/matlabcentral/fileexchange/7842-catstruct
==============

Careful.

Since catstruct() will always consolidate the fields, it means that
it will be susceptible to typos and spelling mistakes.

For example, if default.color='k', but someone inputs an option accidentally using a British spelling like options.colour='g', then default.color will not be overwritten.

These kinds of errors can be hard to detect...