Arrays in Matlab follow the standard rules of arrays. Arrays are numbered lists of related data. Matlab has a number of builtin commands and functions for use with arrays, including length, and the colon notation.
The colon notation produces an array of values, starting with the first value, incrementing (counting) by the second number (which if not present, has a default of 1), and ending when the count passes the final value.
1:1:10 % produces the array [1 2 3 4 5 6 7 8 9 10]
1:10 % also produces the array [1 2 3 4 5 6 7 8 9 10]
1:2:10 % produces the array [1 3 5 7 9]
1:.5:2 % produces the array [1.0 1.5 2.0]
times = .5:.5:10; % produce an array of "times" starting at half a
% second, increasing by half a second, and ending at 10 seconds