In a Matrix, 1_____3 is used to access the elements from 1 to 3 position. code example

Example 1: matlab matrix index

A = [16 5 9; 4 2 11; 7 14 9]; % Create matrix

A(2,3)   % Extract the element in row 2, column 3
ans = 11

A(1:2,2:3) % Extract elements in rows 1 and 2, and columns 2 and 3
ans = 	5	9
		2	11

Example 2: get elements of array matlab

Indicating indexes between ([]) retrieves corresponding values in Matlab. 
array_borders=array([1: end])
As end defines size of the array, retrieve first and last border values of array