I think you are trying to create a hash where the second array element becomes a key and the first element becomes its value; and so on for fourth and third elements, etc. In that case, try this:

my @list = qw(a b c d e f g h);
my %hash = reverse @list;
print map { "$_ -> $hash{$_}\n" } keys %list;

#Prints:
h -> g
b -> a
d -> c
f -> e
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But note that both methods complain if your array length is odd.