If a scalar is the “singular” in Perl, as we described it at the
beginning of Chapter 2, the “plural” in Perl is
represented by lists and arrays.
A list is an ordered collection of scalars. An array is
a variable that contains a list. People tend to use the terms
interchangeably, but there’s a big difference. The list is the data and the
array is the variable that stores that data. You can have a list value that
isn’t in an array, but every array variable holds a list (although that list
may be empty). Figure 3-1 represents a list,
whether it’s stored in an array or not.
Since lists and arrays share many of the same operations, just like
scalar values and variables do, we’ll treat them in parallel. Don’t forget
their differences though.
Figure 3-1. A list with five elements
Each element of an array or list is a separate scalar value. These values are
ordered—that is, they have a particular sequence from the first to the last
element. The elements of an array or a list are indexed
by integers starting at zero and counting by ones, so the first
element of any array or list is always element zero. This also means that
the last index is one less than the number of items in the list.
Since each element is an independent scalar value, a list or array may
hold numbers, strings, undef values, or any mixture of different scalar values. Nevertheless, it’s common to have ...
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