oop - Retrieve property from all instances of one class in Matlab, write value to file -

i automatically retrieve properties instances of same class in workspace.

ex.: have class c1, instances a, b, c, d. each of these have property called x. retrieve x's. how go this?

here's 1 possibility. let's want find doubles in workspace. this

>> x = 12.3; >> y = 45.6; >> z = '789'; 

get list of variables in workspace

>> vars = whos(); 

figure out ones doubles

>> location = strcmp('double',{vars.class}); 

get names

>> names = {vars(location).name}; >> names names =      'x'    'y' 

if wanted array of property x (say want cosine of each double) this

>> n = length(names); >> arr = nan(1,n); >> n = 1:n      obj    = eval(names{n}); # dubious use of 'eval'      arr(n) = cos(obj);       # assign relevant property array    end 

now have

>> arr arr =     0.9647   -0.0469 

---

here's example using custom object. first, put code in file dprotein.m

classdef dprotein     properties         x;         y;     end     methods         function self = dprotein(x, y)             self.x = x;             self.y = y;         end     end end 

now create couple of objects

>> = dprotein(1, 'foo'); # a.x = 1 >> b = dprotein(2, 'bar'); # b.x = 2 

i find of objects of correct class in workspace before

>> vars = whos(); >> location = strcmp('dprotein', {vars.class}); >> names = {vars(location).name}; 

now loop collects array of every object

>> n = 1:length(names)        objects(n) = eval(names{n}); # n.b. important 'objects' not                                     # exist in workspace before line!    end 

and can collect properties this

>> [objects.x] ans =     1    2