How can I access the elements of one array with another array?
显示 更早的评论
I'd like to assign elements to an array in the following manner:
a = zeros(2,2,2);
ix=1;
iy=1;
b = [1,1];
a([ix,iy],:) = b(:)
Where ix and iy represent the position in the 1st and 2nd directions, a in it's 3rd dimension and b are the same length length. For my application ix and iy really need to be in the same array and the method needs to be applicable to N-dimensions. Is there a way to do such an assignment?
采纳的回答
This is really very easy once you put those indices into a cell array:
C = {ix,iy,...,iN,':'};
a(C{:}) = b
Given a numeric vector of indices V:
V = [ix,iy,...,iN];
C = num2cell(V);
a(C{:},':') = b;
or
a(C{:},:) = b;
更多回答（2 个）
Guillaume
2018-12-11
I'm going to assume that [ix, iy] is a 2D array, not a vector as in your example, otherwise your problem is trivially solved with:
indices = [ix, iy];
a(indices(1), indices(2), :) = b(:);
If it's a vector, you will have to convert your Nd subscripts into linear indices with sub2ind. Unfortunately, that means you can't use the colon operator. You have to explicitly list the dimensions.
a = zeros(2, 2, 2);
indices = [1 1;1 2;2 1];
b = [1 2; 3 4; 5 6] %shape of b doesn't matter
linindices = sub2ind(size(a), repmat(indices(:, 1), 1, size(a, 3)), repmat(indices(:, 2), 1, size(a, 3)), repmat(1:size(a, 3), size(indices, 1), 1))
a(linindices) = b
2 个评论
Ryan Potter
2018-12-11
类别
在 帮助中心 和 File Exchange 中查找有关 Resizing and Reshaping Matrices 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
