Colon Notation Function using Matrices

I have two matrices

A = [-1, 2, -3; 4, -5, 6]
B = [0, -1; 2, 10; -4, 3]

And I need help understanding what is happening in these functions:

A(2,2:3)
B(:2) 

ans = 
    -5   6
    
ans = 
    -1
    10
    3

Answer 1

[the cyclist]

A(2,2:3)

means "the 2nd row, 2nd-through-3rd column of A".

B(:,2)

means "all rows, 2nd column of B".

I strongly recommend the MATLAB Onramp tutorial. It covers basic MATLAB like this.

Answer 2

[Awais Saeed]

understand the syntax first. To access an element from a matrix, you need to provide the row and column in which it resides.

% for example
A = magic(4)
A(3,2)          % access element at row = 3, column = 2

: operator means to select a range of rows or coloums

A(:, 2)         % access column = 2 from all rows. Use : to select all rows at once
A(1, :)         % access entire row = 1. Use : to select all columns at once
A(1:3, 2:3)     % access row from 1 to 3 and column from 2 to 3