Error when Indexing and object + OOP

1 次查看(过去 30 天)
Hi,
Can anyone explain me why if I add and objet (PipeLine) to a property (PipeBolt) of another object (Bolt) like:
Bolt(1,1).PipeBolt = PipeLine;
this works well
but if I use:
Bolt(1,1).PipeBolt(N,1) = PipeLine(N,1);
I get an error like: The following error occurred converting from PipeLineObj to double: Conversion to double from PipeLineObj is not possible.
% PipeLine(instance) --> PipeLineObj (class) % Bolt (instance) --> PipeLineBolt (class)
How can I solve this error?

采纳的回答

Adam
Adam 2016-1-27
It likely depends what you are doing before that code. You would be best to pre-size your array of objects with e.g.
Bolt(1,1).PipeBolt = PipeLine.empty(N,0);
to ensure that the property is set to be of the type 'PipeLine', otherwise it will be a double by default, like all variables, so if you didn't explicitly instantiate it and then try to set e.g. its 7th element it will have created it as a double and be expecting a double to be given to it, not some other object type.
In general I initialise all my properties that are to be some other object as e.g.
myProp = SomeClass.empty;
or something like the example above if I expect it to be an array of objects. I cannot remember off the top of my head though - just doing the above and telling it the type of object without presizing may well be enough that your code causing an error would work because it knows the object type beforehand.
  1 个评论
Armindo
Armindo 2016-1-27
Thank you Adam, you are completely right. I do not initialised the object properly.

请先登录,再进行评论。

更多回答(1 个)

Armindo
Armindo 2016-1-27
I solve the other issue but now I have this error:
Assignment has more non-singleton rhs dimensions than non-singleton subscripts
when I do this Bolt(1,1).PipeBolt(2,1)= PipeLineObj.empty
This should not work?
  1 个评论
Adam
Adam 2016-1-28
It should work fine if Bolt(1,1).PipeBolt(2,1) exists and the array is of the correct type.

请先登录,再进行评论。

类别

Help CenterFile Exchange 中查找有关 Matrix Indexing 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by