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Expected one output from a curly brace or dot indexing expression, but there were 2 results, when re-initialize an object array

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I am encountering this issue when I was working on clearing/re-initializing an object array.
A sample code snippet is here:
classdef classObj1
properties
a;
b;
c;
end
end
classdef classObj2
properties (Access = private)
obj1_arr;
end
methods
function addtoArr(obj, e)
obj.obj1_arr(end + 1) = e;
end
function clearArr(obj)
obj.obj1_arr = classObj1.empty(1, 0);
end
function setArr(obj, r)
obj.obj1_arr = r;
end
end
end
Everytime I create an classObj2, I will initialize its property, so the obj1_arr should be an 1d empty array of classObj1.
a = classObj2();
a.setArr(classObj1.empty(1, 0));
and add something to the array, everything is fine until here.
for i = 1:10
o = classObj1();
o.a = 1; o.b = 2; o.c = 3;
a.addtoArr(o)
end
However, when I try to call the clearArr() function, I get the following error message:
Expected one output from a curly brace or dot indexing expression, but there were 2 results.
on the line:
obj.obj1_arr = classObj1.empty(1, 0);
I have done my work on reading some posts for the reason and solution. e.g. using delete(), clear(), or obj.obj1_arr(:) = []; Unfortunately they don't work, and the identical error message is presented on the same line.
What I am trying to do is just clearing all elements in the obj1_arr since I would like to reuse it later without the data set in previous rounds, which is similar to list.clear() in python.
I appreciate any help that can assist me in solving this issue.

Accepted Answer

Shubham Rawat
Shubham Rawat on 17 Mar 2021
Hi Cheng-Hung,
You had done spelling mistake inside the clearArr() function in the following line:
obj.obj1_arr = classObj1.empty(1, 0);
you had written classobj instead it is classObj.
Hope this Helps!
  1 Comment
Cheng-Hung He
Cheng-Hung He on 19 Mar 2021
Hi Shubham,
Thanks for your answer! I have modifed the typo. Moreover, I found that the reason this error presented by Matlab is because the way I call the function.
Originally, I call it with
classObj2_arr.clearArr();
where the classObj2_arr is an array of classObj2, and this way incurs this error.
Instead, I should call it with a for loop:
for i = 1:lenth(classObj2_arr)
classObj2_arr(i).clearArr();
end
Though I have no idea why the first approach cannot be used, this change solves the bug.:)

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