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Is it possible to do multi index command in one line?

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yoohooo's
yoohooo's 2021-4-28
评论： Steven Lord 2021-4-28
For example, if I want to get number of columns in an array I would have to do the following:
A = [1 2; 3 4];
mySize = size(A);
myCol = mySize(2);
It adds 2 lines and an extra variable in my code. Is it possible to put them in one line like:
myCol = size(A)(2);
Somthing similar to this because this is not the correct syntax.
Thank you very much!

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采纳的回答

Matt J
Matt J 2021-4-28
编辑：Matt J 2021-4-28
Not in general, but in the case of your example there is a shorter syntax,
myCol=size(A,2)
  2 个评论
yoohooo's
yoohooo's 2021-4-28
Thank you very much. Ah, I forgot we can also do it this way. This is not a good example, then. But yea, so it's not possible.
Steven Lord
Steven Lord 2021-4-28
Ran in:
For some definition of "one line" it is. Write a function:
A = [1 2 3; 4 5 6];
sz = size(A) % for checking
sz = 1×2
2 3
y = getElement(size(A), 2) % The one line
y = 3
But this has a drawback that the shorter syntax doesn't.
size(A, 3) % A has trailing singleton dimensions
ans = 1
y2 = getElement(size(A), 3)
Index exceeds the number of array elements (2).

Error in solution>getElement (line 7)
y = x(whichone);
function y = getElement(x, whichone)
y = x(whichone);
end

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更多回答（2 个）

Matt J
Matt J 2021-4-28
An approximation of this can be enabled through some incredibly convoluted OOP methods
https://www.mathworks.com/matlabcentral/fileexchange/26570-direct-indexing-of-function-calls-oop-exercise?s_tid=srchtitle
It's not worth it...
Matt J
Matt J 2021-4-28
编辑：Matt J 2021-4-28
Ran in:
This is a generally applicable one line implementation, but probably not what you'd hoped for.
A = [1 2; 3 4];
myCol = subsref( size(A), struct('type','()','subs',{{2}}))
myCol = 2

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