Using brackets with arrays means you're specifying a key in the array to return.
Normally, to create an array, you'd have to do something like:
$myArray = array(1, 2, 3);
Looking at the function [man]range/man however, we see that it returns the new array, so we simply need to take the data that it returns and store it in a variable. Very simple:
$myArray = range(1, 10);