#!/usr/bin/perl
use 5.010;
use strict;
use warnings;

# Data reducer collecting values in a list
my $collect = {
    init => [],
    step => sub { [ @{$_[0]}, $_[1] ] },
    fini => sub { '[' . join(', ', @{$_[0]}) . ']' }
};

# Data reducer averaging numerical values
my $average = {
    init => [ 0, 0 ],
    step => sub { [ $_[0]->[0] + 1, $_[0]->[1] + $_[1] ] },
    fini => sub { $_[0]->[1] / $_[0]->[0] }
};

# Mapping from field indices to data reducers
my @reducers = (
    $collect, $collect, $average, $average, $average, $average
);

# Read data
my %data = ();
while (<DATA>) {
    my ($stamp, $d, $m, $y, @fields) = split /\s+/;
    push @{$data{$stamp}}, \@fields;
}

# Reduce and print data
foreach my $stamp (sort keys %data) {
    my @accumulators = map {
	$_->{init}
    } @reducers;

    foreach my $fields (@{$data{$stamp}}) {
	@accumulators = map {
	    $reducers[$_]->{step}->($accumulators[$_], $fields->[$_])
	} $[ .. $#reducers;
    }

    @accumulators = map {
	$reducers[$_]->{fini}->($accumulators[$_])
    } $[ .. $#reducers;

    say join("\t", $stamp, @accumulators);
}

__DATA__
1094000940 01 09 2004 N49390 E009202 12360 -3 320 017
1094000940 01 09 2004 N49410 E009203 11650 -2 305 016
1094000940 01 09 2004 N49431 E009204 11120 -2.5 339 016
1094001000 01 09 2004 N49451 E009205 10990 -2.2 325 018
1094001000 01 09 2004 N49470 E009199 10460 -1.5 291 018
1094001000 01 09 2004 N49489 E009184 9550 -5.2 250 010