MATLAB: How does MATLAB ‘fill in’ elements when subsetting a matrix by vectors

subsetting

A = [1, 2, 3;
     4, 5, 6;
     7, 8, 9];
 
B = A([end, 1:end], [end, 1:end])
% B =
% 
%      9     7     8     9

%      3     1     2     3
%      6     4     5     6
%      9     7     8     9
Why is the first element of matrix B, i.e. B(1,1), 9?
All the other elements seem to follow the 'classic' rules of concatination/subsetting but how does MATLAB 'fill in' element (1,1)?

Best Answer

Because A(end,end) = 9.
EDIT —
This is a bit more obvious analyzing how MATLAB indexes matrices.
The linear index for ‘A’ is: 
LinA =
     1     2     3     4     5     6     7     8     9
     1     4     7     2     5     8     3     6     9
with the linear index on the first row and the corresponding element in the second row.
The linear indices as you call them (and MATLAB then calculates them) are: 
LinIdx =
     9     7     8     9     3     1     2     3     6     4     5     6
and the corresponding elements of ‘A’ are: 
LinB =
     9     7     8     9     3     1     2     3     6     4     5     6
     9     3     6     9     7     1     4     7     8     2     5     8
again with the linear index on the first row and the corresponding element in the second row.
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