MATLAB: How to access cells of n-dimensional array without colon operator

colon n-dimensional n-dim ndim arrays matrixesevalMATLAB

I need to develop a function that can accept any n-dimensional arrays. It should access cells of the arrays in the following way:
mat(1:end-1,       :,       :, ...       :);
mat(      :, 1:end-1,       :, ...       :);
mat(      :,       :, 1:end-1, ...       :);
mat(      :,       :,       :, ... 1:end-1);
And also by other similar combinations for more then one dimension, e.g.:
mat(1:end-1,       :, 1:end-1, ...       :);
How can it be done in a smarter way, so I do not need to consider all cases manually, and it can be universal for any number of dimensions?
I was looking for something as:
new_mat = function(mat, (vector with dimensions to be used), (vectors used to access cells, e.g., 1:end-1));
For example it could be:
new_mat = function(mat, [1 3], [1:end-1; 2:end]);
which is equivalent to:
new_mat = mat(1:end-1,       :, 1:end-1, ...       :);
GREAT THANKS!

Best Answer

That was a fun post-lunch challenge, thanks!
extractFromND(magic(3),[1 2],[2 3;3 3])
It does not accept end you have to pass in the calculation yourself, e.g.
size(x,4)-1 %equivalen to end-1 in dim 4
The function
function Mextract = extractFromND(M,dim,datarange)
% EXTRACTFROMND extract data range in dim from M
%











%Usage:
%   -Mextract = extractFromND(M,dim,datarange);
%
%Inputs:
%   -M:   nd matrix
%   -dim: dimensions that the rows of datarange use
%   -datarange: [dim x 2] where each row is the range in low/high in dim
%
%Outputs:
%   -MExtract: M not including data outside of datarange in dim of M
%
%
%Examples:
%
%   x = ones(3,3,3,3,3);
%   x2 = extractFromND(x,[1 5],[2 3;1 2]);
%   size(x2);
%
%See Also: colon
%
%
%TODO: make datarange nx3 with middle column the stride
%
%
% Copyright 2013 The MathWorks, Inc. 
% SCd 735494
%
      %Rudimentary error checking
      assert(nargin==3,'Exactly three inputs expected');
      ndM = ndims(M);
      assert(max(dim)<=ndM,'Can''t pull from more dimensons than we have');
      ned = numel(dim); %numel extract dimensions
      assert(size(datarange,1)==ned,'datarange should have the same number of rows as dim');   
      szM = size(M);
      assert(all(szM(dim).'>=datarange(:,2)),'out of range datarange');
      %Engine:
      %Build index vector
      idx = repmat({':'},1,ndM);
      for ii = 1:ned
          idx{dim(ii)} = datarange(ii,1):datarange(ii,2);
      end
      %Extract from M:
      Mextract = M(idx{:});
end
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