mmv2struct.m

《精通matlab7》“mastering matlab 7”的代码。

function varargout=mmv2struct(varargin)
%MMV2STRUCT Pack/Unpack Variables to/from a Scalar Structure. (MM)
% MMV2STRUCT(X,Y,Z,...) returns a structure having fields X,Y,Z,...
% containing the corresponding data stored in X,Y,Z,...
% Inputs that are not variables are stored in fields named ansN
% where N is an integer identifying the Nth unnamed input.
%
% MMV2STRUCT(S)assigns the contents of the fields of the scalar structure
% S to variables in the calling workspace having names equal to the
% corresponding field names.
%
% Example: X=zeros(3); Y='Testing123'; Z=cell(2,3);
% S=MMV2STRUCT(X,Y,Z,pi) returns a structure S containing the following
% fields: S.X  S.Y  S.Z  S.ans1 each containing the contents of the
% corresponding variables.
% MMV2STRUCT(S) creates or overwrites variables X, Y, Z, ans1 in the caller
% with the contents of the corresponding named fields.
%
% [A,B,C,...]=MMV2STRUCT(S) assigns the contents of the fields of the
% scalar structure S to the variables A,B,C,... rather than overwriting
% variables in the caller. If there are fewer output variables than
% there are fields in S, the remaining fields are not extracted.
%
% Using the above example, [A,B,C]=MMV2STRUCT(S) returns the contents of
% S.X in A, S.Y in B, and S.Z in C and does not extract S.ans1 because
% no output argument was provided for it. FIELDNAMES(S) determines the
% order in which the fields in S are assigned to the output arguments
% of MMV2STRUCT.

% D.C. Hanselman, University of Maine, Orono, ME 04469
% 4/28/99, 9/29/99, renamed 10/19/99, 2/20/01
% Mastering MATLAB 6, Prentice Hall, ISBN 0-13-019468-9

if nargin==0
   error('Input Arguments Required.')
   
elseif nargin==1 % Unpack Unpack Unpack Unpack Unpack Unpack
   arg=varargin{1};
   if ~isstruct(arg)||length(arg)~=1
      error('Single Input Must be a Scalar Structure.')
   end
   names=fieldnames(arg);
   %S.type='.';
   if nargout==0 % assign in caller
      for i=1:length(names)
         %S.subs=names(i); % for speed, inline getfield operation
         %assignin('caller',names{i},subsref(arg,S))
         assignin('caller',names{i},arg.(names{i}));
      end
   else          % dump into variables
      varargout=cell(1,nargout);
      for i=1:min(nargout,length(names))
         %S.subs=names(i); % for speed, inline getfield operation
         %varargout{i}=subsref(arg,S);
         varargout{i}=arg.(names{i});
      end
   end
   
else % Pack Pack Pack Pack Pack Pack Pack Pack Pack Pack
   args=cell(2,nargin);
   num=1;
   for i=1:nargin % build cells for struct call
      args(:,i)={inputname(i);varargin{i}};
      if isempty(args{1,i})
         args{1,i}=sprintf('ans%d',num);
         num=num+1;
      end
   end
   varargout{1}=struct(args{:}); % comma-separated list!
end