No, you have it backwards. The hash equivalent of
@$ar[0] (or @$ar[0, 1, 2])
is
@$hr{a} (or @$hr{'a', 'b', 'c'})

%$hr{a} is nonsense. Read about slices in perldata

By the way, you shouldn't use slices for single elements.
@$ar[0] and @$hr{a}
should be
$$ar[0] and $$hr{a}

Remember: When using an index on a hash or an array, the sigil is of the type returned/assigned. Slices return/accept a list, so @ is used. When refering to a single element, $ is used. % is never used when an index is specified.

Update: Here's a table which should help:
Direct Using References
Syntax 1* Syntax 2
array element $a[0] ${$ar}[0] $ar->[0]
slice @a[0,1,2] @{$ar}[0,1,2]
unindexed @a @{$ar}
hash element $h{'a'} ${$hr}{'a'} $hr->{'a'}
slice @h{'a','b','c'} @{$hr}{'a','b','c'}
unindexed %h %{$hr}

* – The curly brackets around $ar and $hr are optional.

In reply to Re^2: A better understanding of array and hash references by ikegami
in thread A better understanding of array and hash references by jeanluca

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