1BRC implementations in Python and Perl

calculate-average.pl

use strict;
use warnings;
use Time::HiRes qw(gettimeofday tv_interval);

my $start_time = [ gettimeofday ];
my $filename   = '../../data/weather-data-100K.csv';
$filename      = $ARGV[0] if (@ARGV);
print "filename: $filename\n----\n";

my %data;
open my $file, '<', $filename or die "cannot open $filename: $!";
while (my $line = <$file>) {
    chomp $line;
    my ($station, $temperature) = split ';', $line;

    $data{$station}{count}++;
    $data{$station}{sum} += $temperature;
    if (!defined $data{$station}{min} || $temperature < $data{$station}{min}) {
        $data{$station}{min} = $temperature;
    }
    if (!defined $data{$station}{max} || $temperature > $data{$station}{max}) {
        $data{$station}{max} = $temperature;
    }
}
close $file;

foreach my $station (sort keys %data) {
    my $cnt = $data{$station}{count};
    my $avg = $data{$station}{sum} / $cnt;
    my $min = $data{$station}{min};
    my $max = $data{$station}{max};
    printf "%s: %.1f, %.1f/%.1f (%d)\n", $station, $avg, $min, $max, $cnt;
}

print '----\n';
my $end_time     = [ gettimeofday ];
my $elapsed_time = tv_interval($start_time, $end_time);
print STDERR "[perl] elapsed $elapsed_time seconds, $filename\n";

calculate-average.py

import time, sys

start_time = time.time()
filename   = '../../data/weather-data-100K.csv'
if len(sys.argv) > 1:
    filename = sys.argv[1]
print('filename:', filename, '\n----')

data = {}
with open(filename, encoding='utf-8') as file:
    for line in file:
        station, temperature = line.strip().split(';')
        temperature = float(temperature)
        next  = {'count': 1, 'sum': temperature, 'min': temperature, 'max': temperature}
        entry = data.get(station)
        if entry:
            next['count'] = 1 + entry['count']
            next['sum']   = temperature + entry['sum']
            next['min']   = min(temperature, entry['min'])
            next['max']   = max(temperature, entry['max'])
        data[station] = next

for entry in dict(sorted(data.items())).items():
    station, a = entry
    print('{}: {:+.1f} C, {:+.1f}/{:+.1f} ({})'.format(
        station, a['sum'] / a['count'], a['min'], a['max'], a['count']))

print('------')
end_time     = time.time()
elapsed_time = end_time - start_time
print('[python] elapsed {:.2f} seconds, {}'.format(elapsed_time, filename), file=sys.stderr)