c:\@Work\Perl\monks>perl -le
"use strict;
 use warnings;
 ;;
 use Test::More 'no_plan';
 use Test::NoWarnings;
 ;;
 use Data::Dump qw(dd);
 ;;
 my $aref = [
   { 'cname' => 'Smart Parking',     'balance' => 10.12, },
   { 'cname' => 'Smart Parking',     'balance' => 10.22, },
   { 'cname' => 'Smart Parking',     'balance' => 10.32, },
   { 'cname' => 'Highview Parking',  'balance' => 20.12, },
   { 'cname' => 'Highview Parking',  'balance' => 20.22, },
   { 'cname' => 'Highview Parking',  'balance' => 20.32, },
   { 'cname' => 'Highview Parking',  'balance' => 20.42, },
   { 'cname' => 'ParkingEye',        'balance' => 30.12, },
   { 'cname' => 'ParkingEye',        'balance' => 30.22, },
   ];
 ;;
 my %lot_and_order;
 my %merged;
 for my $hr (@$aref) {
   my $lot_name = $hr->{'cname'};
   $lot_and_order{$lot_name} = keys %lot_and_order
     unless exists $lot_and_order{$lot_name};
   $merged{$lot_name}{'balance'} += $hr->{'balance'};
   $merged{$lot_name}{'total'}++;
   }
 dd 'merged', \%merged;
 dd 'lot and order', \%lot_and_order;
 ;;
 my @out =
   map  { { 'cname' => $_,  'balance' => $merged{$_}{'balance'},  'total' => $merged{$_}{'total'} } }
   map  { $_->[0] }
   sort { $a->[1] <=> $b->[1]  }
   map  { [ $_, $lot_and_order{$_} ] }
   keys %lot_and_order
   ;
 dd 'in lot order', \@out;
 ;;
 my $ar_expected = [
   {
     'cname' => 'Smart Parking',
     'balance' => '30.66',
     'total' => '3',
   },
   {
     'cname' => 'Highview Parking',
     'balance' => '81.08',
     'total' => '4',
   },
   {
     'cname' => 'ParkingEye',
     'balance' => '60.34',
     'total' => '2',
   },
 ];
 ;;
 is_deeply \@out, $ar_expected, 'merged in lot order';
 ;;
 done_testing;
 exit;
"
(
  "merged",
  {
    "Highview Parking" => { balance => "81.08", total => 4 },
    ParkingEye         => { balance => "60.34", total => 2 },
    "Smart Parking"    => { balance => "30.66", total => 3 },
  },
)

(
  "lot and order",
  { "Highview Parking" => 1, ParkingEye => 2, "Smart Parking" => 0 },
)

(
  "in lot order",
  [
    { balance => "30.66", cname => "Smart Parking", total => 3 },
    { balance => "81.08", cname => "Highview Parking", total => 4 },
    { balance => "60.34", cname => "ParkingEye", total => 2 },
  ],
)

ok 1 - merged in lot order
1..1
ok 2 - no warnings
1..2