multidimensional colon operator?
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I want to do something like that below: copy an N-dimensional array into a N+1-dimensional array at index t in the last dimension. Can this be done efficiently and cleaner than umpteen if-tests or nasty permutes?
function A = insert_x_into_A(A,x,t)
if ndims(A) == 2
A(:,t) = x;
elseif ndims(A) == 3
A(:,:,t) = x;
elseif ndims(A) == 4
A(:,:,:,t) = x;
...
end
I think that something like the pseudo-code below would be neat
function A = insert_x_into_A(A,x,t)
A(colon(ndims(x)),t) = x;
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Jan
el 4 de Feb. de 2011
Two approaches: 1. Reshape the matrix at first:
function A = insert_x_into_A(A,x,t)
siz = size(A);
A = reshape(A, [], siz(end));
A(:, t) = x(:);
A = reshape(A, siz);
2. Use a cell as index vector: EDITED: Cleaned up with Bruno's suggestion.
function A = insert_x_into_A(A,x,t)
idx(1:ndims(A) - 1) = {':'};
A(idx{:},t) = x;
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Más respuestas (1)
Matt Fig
el 4 de Feb. de 2011
If you want to get real evil:
function A = insert_x_into_A(A,x,t)
col = repmat(':,',1,ndims(A)-1);
eval(['A(',col,'t) = x;'])
Though I don't know why you would need such a specific function.
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