How can i get the n-2-dimensional submatrix from a n-dimensional matrix?

Question

i have a n-dimensional matrix from which i want the n-2 -dimensional submatrix

For example:

if i have a matrix A that is 6x5x4x3x2, i want to get for example the matrix

B = A(1,:,:,:,2);

This is easy if the amount of dimensions is fixed, but how can i do this for variable dimensions without having to handle a specific case for each number of dimensions?

Bad:
n = length(size(A));
if (n == 2)
  B = A(1,2)
else if (n == 3)
  B = A(1,:,2);
else if (n == 4)
  B = A(1,:,:,2);
else if (n == 5)
  B = A (1,:,:,:,2);

 ...

 Good:
 B=A(1,<some cool operator/expression>,2);

A minor adaptation of [this](http://stackoverflow.com/q/22537326/2586922) will solve your problem — Luis Mendo, May 09 '14 at 12:43

score -1 · Accepted Answer · edited May 23 '17 at 12:13

-1

Thanks to the link provided in the comment, i was able to solve it like this:

n = ndim(A);
if (n <= 2)
   B = A(1,2);
else
   colons = repmat({':'},[1 n-2]);
   B = A(1,colons{:},2);

edited May 23 '17 at 12:13

Community

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answered May 09 '14 at 13:48

Martze

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How can i get the n-2-dimensional submatrix from a n-dimensional matrix?

1 Answers1