Writing "this" class' properties?

Hi, I am new to Matlab classes. I want to change the value of some properties in a function called ChangeProperties from within the class. But I can't do it. What am I doing wrong?

classdef agent_type
  properties
    v
    id
  end
  methods
    function p=agent_type(i)
      p.id=i;
      p.v=10*randn(1,2);
    end

   function y=ChangeProperties(this,step)
     [this.v(step,:)]=zeros(1,2); 
      y=[this.v(step,:)];
   end
 end
end

when I run: agent.ChangeProperties(2) I get a random 1x2 vector. It should be a zero 1x2 vector. Why does this.v remain the same?

Thank you

[Andrew Newell]

I'm not sure what you're trying to do. Do you want to change your agent and also return a vector, or just change your object?

[Andrew Newell]

Also, what is step supposed to do? As written, it is adding rows when step > 1.

Answer 1

[Andrew Newell]

I'm just guessing at what you're trying to do, but here is a different version of your method:

function y=ChangeProperties(this,vnew)
  y = this;
  y.v=vnew;
end

Then if you run

a = agent_type(1);
a = a.ChangeProperties([0 0])

you get

a = 

agent_type

Properties:
   v: [0 0]
  id: 1

[Eleftherios Ioannidis]

Great answer Andrew, as always. Thank you. Also, thank you for the pm.