my @data_list = ( { key => 'a', value => 1 }
                  , { key => 'b', value => 2 }
                  , { key => 'c', value => 3 }
                );

#this line does the conversion
my %hData = map { $_->{key} => $_->{value} } @data_list;

print "@{[%hData]}\n";