This code:

foreach (1..3) {
  push @hashes, {};
}
[download]

does the same thing (but faster and cleaner) as this code:

foreach (1..3) {
  my %any_name;
  push @hashes, \%any_name;
}
[download]

At the end of the each loop in the second example, the %any_name hash would normally vanish, but because a *reference* to it is saved, the hash itself still floats in memory, with no name associated with it. Since a reference is a kind of scalar, it can be stored in the array just like any other scalar. The anonymous hash constructor, {}, allows you to avoid any %temp_hash that you did not need to refer to by name.

See also:

• perlreftut - Mark's very short tutorial about references
• perlref - Perl references and nested data structures