my $ref;
$ref = [
          {
           "key1" => 'a',
           "key2" => 'b',
          },
          {
           "key1" => 'c',
           "key2" => 'd',
          },
        ];

foreach $hashref (@{$ref}) {
    print $hashref->{'key1'};
}#foreach

##</code><code>##

for (my $item = 0; $item <= $#{$ref}; $item++) {
    print $item;
    print $ref->[$item]->{'key1'};
}#for

##</code><code>##

my $item = 0;
foreach $hashref (@{$ref}) {
    print $hashref->{'key1'};
    $item++;
}#foreach

##</code><code>##

my $ref;
$ref->[0]->{'key1'} = "a";
$ref->[5]->{'key1'} = "b";
my $item = 0;
foreach $hashref (@{$ref}) {
    print $item;
    print $hashref->{'key1'};
    $item++;
}#foreach