Likewise, you can add to or modify the values of an
existing array by simply referencing the array by number.
For example, to add an element to @available_colors,
you might use the following line:
$available_colors[4] = "orange";
Thus, @available_colors would include the elements:
red, green, blue, brown, and orange.
You can also use this method to overwrite an element in
a list array. To change a value in @available_colors, you
might use the syntax:
$available_colors[0] = "yellow";
Now, the elements of @available_colors would be:
yellow, green, blue, brown, orange.
