Besies that you say "list" in one place and "array" in another which may indicate some confusion on your part (or mine), that sounds like a strange (if not dubious) think to want to do.

But, if your sure it is what you need, here are two ways. Judge the comparative merits for yourself:

sub listToIndexedHashRef{ 
    my $n=0; 
    my %hash = map{ $n++, $_} @_; 
    return \%hash 
};;

my $hashRef = listToIndexedHash( qw[the quick brown fox ] );;

pp $hashRef;;
{ "0" => "the", 1 => "quick", 2 => "brown", 3 => "fox" }

sub listToIndexedList{ 
    my $n=0; 
    return map{ $n++, $_} @_; 
};;

my %hash = listToIndexedList( qw[the quick brown fox ] );;

pp \%hash;;
{ "0" => "the", 1 => "quick", 2 => "brown", 3 => "fox" }
[download]