I would like to do something like the following code where all 3 properties is statically known to be size (1,10)
without having to explicitly re-write the 10
at the property declaration.
classdef Example
properties(Constant)
length_of_vector = 10;
end
properties
x_data(1, Example.length_of_vector);
y_data(1, Example.length_of_vector);
z_data(1, Example.length_of_vector);
end
end
This syntax is not valid, is there a way to accomplish this without re-writing 10
in all three places? My real use-case has several dimensions that have statically known sizes and I'd really like to be able to specify what length they are in the declaration so that maintainers will know what size is expected but the constants can be changed and it automatically updates all the property sizes that depend on it.
CodePudding user response:
Example.length_of_vector
is valid inside methods of the class, and outside the class as well. I guess it is not valid in your code because MATLAB is still loading the class definition when it encounters Example.length_of_vector
, but Example
is not yet loaded.
I can think of two ways to work around this:
Declare the size of the properties in the constructor:
function obj = Example obj.x_data = zeros(1, Example.length_of_vector); %... end
Define your constants in a different way. A common method is to use a function. You can put this function at the end of your
classdef
file, outside theclassdef
block:classdef Example properties x_data(1, length_of_vector); y_data(1, length_of_vector); z_data(1, length_of_vector); end end function l = length_of_vector l = 10; end
With this method, your constant is private to your class, it cannot be accessed from outside. To make it public, you would have to add a static method to your class that returns the constant.
CodePudding user response:
hope the code help:
classdef Example
properties
length_of_vector = 10;
x_data ;
y_data ;
z_data ;
end
methods
% if u wont change the properties use function obj = Example()
% if u want to change the properties use function obj = New_value(obj)
function obj = New_value(obj)
obj.x_data = zeros(1, obj.length_of_vector);
obj.y_data = zeros(1, obj.length_of_vector);
obj.z_data = zeros(1, obj.length_of_vector);
end
end
end
useCase :
a = example;
outPut :
a =
length_of_vector: 10
x_data: []
y_data: []
z_data: []
then :
a.New_value;
outPut :
a =
length_of_vector: 10
x_data: [0 0 0 0 0 0 0 0 0 0]
y_data: [0 0 0 0 0 0 0 0 0 0]
z_data: [0 0 0 0 0 0 0 0 0 0]
when you want to change the length:
a.length_of_vector = 15;
a.New_value
outPut :
a =
length_of_vector: 15
x_data: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
y_data: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
z_data: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]