Strange behavior when initializing empty cell in struct()
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Structs initialized with an empty cell using both {} and cell.empty within a struct() returns an empty struct object.
The following function reproduces that:
function print_hello_world()
obj = struct(MyProp=123, MyOtherProp={}); % or MyOtherProp=cell.empty
disp(obj)
disp(isempty(obj))
end
The obj variable is empty when running print_hello_world.
I have resorted to the following to go around this issue:
function print_hello_world()
obj = struct(MyProp=123);
obj.MyOtherProp = {};
disp(obj)
disp(isempty(obj))
end
The value of obj is as expected when running the above.
1 件のコメント
Stephen23
2024 年 6 月 20 日
"Structs initialized with an empty cell using both {} and cell.empty within a struct() returns an empty struct object."
Exactly as documented here: https://www.mathworks.com/help/matlab/ref/struct.html#d126e1620618
回答 (1 件)
Aquatris
2024 年 6 月 20 日
編集済み: Aquatris
2024 年 6 月 20 日
If you want to define the property as empty, then you should use '[]' instead of '{}'.
obj = struct(MyProp=123, MyOtherProp=[]);
disp(obj)
s = struct(field1,value1,...,fieldN,valueN) creates a structure array with multiple fields.
- ...
- If any value input is an empty cell array, {}, then output s is an empty (0-by-0) structure. To specify an empty field and keep the values of the other fields, use [] as a value input instead.
1 件のコメント
Stephen23
2024 年 6 月 20 日
Or if an empty cell array is required:
obj = struct(MyProp=123, MyOtherProp={{}});
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