Make a matrix B of the first, fourth and fifth row and the first and fifth column from matrix A in OCTAVE

Question

I have matrix AA =

 5    10    15    20    25
10     9     8     7     6
-5   -15   -25   -35   -45
 1     2     3     4     5
28    91   154   217   280

And i need to make a matrix B of the first, fourth and fifth row and the first and fifth column from matrix A. How can i do it?

Answer 1

>> B = A([1,4,5],[1,5])
B =
 5      25
 1       5
28     280

You should look up how to use index expressions in the Matlab and Octave language to extract and work with submatrices.

See the Octave help on Index expressions: https://octave.org/doc/latest/Index-Expressions.html