try to manage a dynamic list of classinstances

Question

jeff wu 2012-3-24

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/33355-try-to-manage-a-dynamic-list-of-classinstances

hi its me again, i figured a lot out already thanks to your help, but there are still some misteries. i got this:

    classdef node<handle
      properties 
          x;
          y;
          bearing=0;
      end % properties
      methods
          function obj = node(x,y)
              obj.x=x;
              obj.y=y;
          end%functions
      end%methods
  end %class

and this:

classdef manlists 
    properties
        nodelist={}
        stablist={}
        materiallist={}
        formlist={}    
    end
    methods
        function f = manlists()
            f.nodelist={node(1,2);node(2,3)};% as a try, and here works the node instance
            f.stablist={};
            f.materiallist={};
            f.formlist={}    ;
        end
        function h = grN(obj)
            h = size(obj.nodelist,1);
        end
        function h = AddNode(a,b)
           h.nodelist{end+1} =node(a,b) 
        end
    end
end

but it doesnt work like i expect it to

in the command window it works

>> man = manlists;
>> man.nodelist{end+1}=node(1,2)

man =

manlists
Properties:
      nodelist: {3x1 cell}
      stablist: {}
  materiallist: {}
      formlist: {}
Methods

but inside the class i get this error:

>> man.AddNode(1,2)
??? Error using ==> AddNode
Too many input arguments.

i tried arround for several hours but i cant figure it out please help

thanks

3 个评论
显示 1更早的评论隐藏 1更早的评论

Daniel Shub 2012-3-25

It is also strange to me that nodelist is a cell array instead of an array of class node.

per isakson 2012-3-25

Why do you use cell arrays and not ordinary arrays?

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Daniel Shub 2012-3-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/33355-try-to-manage-a-dynamic-list-of-classinstances#answer_41990

在 MATLAB Online 中打开

The call

man.AddNode(1,2)

is converted behind the scenes to

AddNode(man, 1, 2)

which has three arguments, but AddNode only takes 2 arguments. What I think you "want" is

function h = AddNode(h,a,b)

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

jeff wu 2012-3-26

thanx a lot,

it works now in the way man = manlists; man = man.Addnode(1,2);

but is there a way to add a node without assigning man again;

actually i thought and what i wanted to do is that by calling man.Addnode(1,2) that one would automatically be added to the nodelist without deleting the previous.

请先登录，再进行评论。

Answer 2

per isakson 2012-3-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/33355-try-to-manage-a-dynamic-list-of-classinstances#answer_41994

在 MATLAB Online 中打开

Try

man = manlists;
man.nodelist(end+1) = node(1,2);
man = man.AddNode(1,2);
man.grN

with these two classes

classdef node < handle
    properties
        x;
        y;
        bearing=0;
    end % properties
    methods
        function this = node(x,y)
            this.x=x;
            this.y=y;
          end%functions
      end%methods
  end %class
classdef manlists 
    properties
        nodelist = node.empty
    end
    methods
        function this = manlists()
            this.nodelist(end+1:end+2,1)=[ node(1,2); node(2,3)];
        end
        function sz = grN( this )
            sz = size( this.nodelist, 1 );
        end
        function this = AddNode( this, a ,b )
           this.nodelist(end+1) = node( a, b ); 
        end
    end
end

2 个评论
显示无隐藏无

Daniel Shub 2012-3-25

My guess is that at some point Wu is going to subclass node and therefore need to use a heterogeneous array. As it stands now, I like your way with standard arrays.