Arrays

Arrays (whose names all begin with @) are used to store collections of objects when it makes sense to index those objects by number. Square brackets ([ and ]) are used to specify the index or indices of the elements you are interested in. When the value inside the square brackets is a single number, or a variable which evaluates to a single number, you should refer to the variable with a dollar sign, not an at sign, since such an expression is referring to a scalar value. On the other hand, when the value inside the square brackets is a list, the expression will refer to another array of elements (sometimes referred to as a slice), and the at sign is once again appropriate.

You can initialize an array by separating the array elements with commas, and surrounding them with parentheses:

     @values = (1,4,7,9);

The following expressions show some of the ways you can access array elements:

 $x = $values[0];           # sets x equal to 1
 $i = 2;
 print $values[$i];         # prints 7
 @xodd = @values[1,3];      # sets xodd equal to (4,9) 
 @indices = (1,3)
 @xodd = @values[@indices]; # same as previous @xodd value

Note that either a number or a variable containing a number can be used as a subscript of an array. In fact, any expression which results in a number or an array of numbers can be used as a subscript.