Cannot call or index into a temporary array error message

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I am trying to access the elements of a 1 by 2 variable that is defined by a function handle, p2r, but when I define a separate function handle p22r to do this I get the error message Cannot call or index into a temporary array. Is there a way I can access the elements of a 1 by 2 vector that has not yet been initialized?
r2p = @(x) [abs(x) rad2deg(angle(x))];
p2r = @(x) x(1)*exp(1i*deg2rad(x(2)));
pm = @(x,y) [x(1)*y(1) x(2)+y(2)];
pd = @(x,y) [x(1)/y(1) x(2)-y(2)];
p22r = @(x,y) p2r([x y])(:,1);

Answers (1)

Tarunbir Gambhir
Tarunbir Gambhir on 27 Jan 2021
MATLAB does not support syntax which directly index the function call return value, like "p2r([x y])(:,1)". It is recommended that you use temporary intermediate variables for indexing in a function declaration, rather than using anonymous function for 'p22r'.
As an alternative, however, you could use workaround with some limitations on the result. For example, if you need to return a value at the particular index (1,1) of 'p2r([x y])', you can use getfield or subsref functions as
p22r = @(x,y) getfield(p2r([x y]),{1,1});
p22r = @(x,y) subsref(p2r([x y]), struct('type', '()', 'subs', {{1, 1}}));
  1 Comment
Liang Zhang
Liang Zhang on 16 Jul 2023
Edited: Liang Zhang on 16 Jul 2023
This is just an unnecessary complication. I am wondering why this syntax is not supported while Octave and Scilab both support this syntax. The syntax could save life for some while.

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