How can i extract sub matrix from basic matrix

Hello. My basic matrix is

B=[-1,1,1,5+i*2;0,-1,0,20+i*10;0,0,-1,10+i*3;1,0,0,0;30+i*30,50+i*50,60+i*60,0]

Sub matrix is A

A=[-1,1,1;0,-1,0;0,0,-1;1,0,0]

Answer 1

[Walter Roberson]

   A = B(1:4, 1:3);

[Dulam Sai Namratha Naidu]

could you please explain me this code.

[welzheimerwald]

@Dulam Sai Namratha Naidu it generates a 4x3 sub matrix of matrix B with rows 1,2,3,4 and colums 1,2,3 from matrix B.

Answer 2

[Navadeep Ganesh U]

A=B([1,2,3],[1,2,3])

means, We need to extract B's 1st 2nd and 3rd row along with B's 1st 2nd and 3rd column.

By this you can get approprite answer.

It can also be written as A=B([1:3],[1:3])

LoL,...............6yrs later

[Griffen Morrison]

Hey if your explination didnt help the original poster it some random person years later to understand the code. Thanks!

[Wehann Landsberg]

Yeah, someone like me :)

[aniss skalli]

and like me

[Rafael Olaru]

or like me :D

[Brandon Fenske]

THANK YOU

Answer 3

[sunny]

B=[-1,1,1,5+1i*2;0,-1,0,20+1i*10;0,0,-1,10+1i*3;1,0,0,0;30+1i*30,50+1i*50,60+1i*60,0];
B(:,end)=[];
B(end,:)=[];