Deleting Row and Column

I am doing a project with matrices. I want to change the size of the matrix by deleting the last 2 rows and the last 2 column. I want to go from 0.01 to 0.15 in steps of 0.01. When I display Q1 I am able to delete the last 2 columns but the the last 2 rows and then when I try to delete the rows (disp Q2) it deleted the rows but not the columns. I want BOTH the last two ROW AND last two COLUMN to be deleted from the Matrix P. Any help is appreciated!!!!

P = [0.1 0.75 0 0 0.15 0; 0 0.1 0.8 0 0.10 0; 0 0 0.15 0.75 0.1 0; 0 0 0 0.1 0.1 0.8; 0 0 0 0 1 0; 0 0 0 0 0 1];
disp(P)
for v = 0.01:0.01:0.15
    P(1,1) = v + P(1,1);
    %disp(P)
    Q1 = ([:,1 2 3 4]);
    disp(Q1)
    Q2 = P([1 2 3 4],:);
    %Q2 = P(:, [5 6]);
    disp(P)
end

Answer 1

[KSSV]

If A is your matrix, you can remove last two rows and columns using:

[m,n] = size(A) ; 
A(m-1:m,:) = [] ;   % removes last two rows 
A(:,n-1:n) = [] ;   % removes last two columns

[Imani DaSilva]

when I try this method i am getting an error saying "Index in position 1 is invalid. Array indices must be positive integers or logical values." it prints out the first matrix correctly and then runs into that error.

[KSSV]

Show us the code which you have tried.

Answer 2

[James Tursa]

Q = P(1:end-2,1:end-2);

[Imani DaSilva]

This worked! Thank you. One final question, if i wanted to just get the last two colums of the matrix without the last 2 rows, how would I go about doing that?

[Imani DaSilva]

from what i understand P(1:end-2,1:end-2) is for the subtracting the last two rows and colums starting from column 1 and row 1. So if i wanted to get the last 2 columns without the last 2 rows. I tried the same concept with removing the last 2 rows but extracting the last 2 columns and it is just giving me a vector of 1's. But i would want

0.1500 0

0.1000 0

0.1000 0

0.1000 0.8000

(1.0000 0) ->minus this row

(0 1.0000) -> minus this row

[Imani DaSilva]

I figured it out! thanks for the help