Getting a field in a Class

I am trying to define a Class. When I create an object of the Class, I want to be able to get one of its properties. I have made it so when I have a 'get' method I can return the property when I use the syntax:

b = newobject(4); % My class only needs to take one int value

val = get(b, 'SomeVal') % this just returns a value

How do I make make my Class so that when I write:

val = b.SomeVal

I get the same result?

Also, this dynamic preview is really slow, is there a way to disable it?

Hmm, having trouble posting the class that I made. It's very poorand I am going to move on and come back to it later

[Walter Roberson]

Sorry, there is no way to disable the dynamic preview of the Answers system. The problem is known, and I do not know why it is taking so long to fix.

[Daniel Shub]

Can you post some more code about your class. Is your class a subclass of hgsetget? How have you defined get and how have you defined the property SomeVal? What do you currently get when you do b.SomeVal?

Answer 1

[Lucas García]

You should now be able to do:

b.get('SomeVal')

Or your access method for the SomeVal property has to be defined as public:

properties (GetAccess = public, SetAccess = private)
   SomeVal
end

and at some point in the constructor method do:

function obj = newobject(value)
   obj.SomeVal(end+1) = value; % end+1 to make it vector based
end

Then you will be able to do:

b.SomeVal

[Stagleton]

hmm, I have not been able to get this to work. Where should I make this properties declaration?

It also does not work to write

b.get('SomeVal')

I am probably not implementing these things correctly.

Can you clarify further?

[Lucas García]

Question: which MATLAB version are you using?

[Stagleton]

2010 B

[Lucas García]

Here is a simple class of what your code could look like:

classdef newobject

properties (GetAccess = public, SetAccess = private)

SomeVal

end

methods

function obj = newobject(value)

obj.SomeVal = value;

end

end

end

[Stagleton]

ok, I will try this out.

Here is one method I created for my class in order to get it to work (its a bit messy and there is probably a better way to do it):

function [ B ] = subsref( A,L )

%SUBSREF Summary of this function goes here

% Detailed explanation goes here

if (strcmp(L(1).type,'.') && strcmp(L(1).subs, 'Value'))

B=A.Value;

end

end

[Stagleton]

this seems like a decent way of writing it that has worked for me:

function [ B ] = subsref( A,L )

%SUBSREF Summary of this function goes here

% Detailed explanation goes here

switch L(1).type

case '.'

switch L(1).subs

case 'Value'

B=A.Value;

end

end

end

[Stagleton]

when I write:

properties (GetAccess = public, SetAccess=private)

outp.Value

end

the 'end' connects with the constructor at the top. I can't seem to get the 'properties' method/function to work

[Daniel Shub]

Something is wrong. First, I am pretty sure outp.Value is not a valid property name and that property names cannot have "." in them. Second, you do not need a subsref method to do this. Third, your subsref method is so simple that it is going to cause all sorts of problems as you expand the class. I would suggest posting your entire simplified class file with all the methods.

[Stagleton]

1st: yes, it seems I do not understand how to use the method 'properties'. I thought a property could be one of the fields in the structure that is created in the constructor....I suppose not?

2nd: Maybe not, but I am going through one of the courses on this site and I am trying to understand how to write classes in matlab. There may be another way of doing what I am trying to do without a subsref overriding method, and I am up for learning that as well.

3rd: I will post my class when I can. sry computer here doesnt have it and im heading on vacation.....

whoops fire alarm. see you