Re: count sort & output

An OO-style solution:

test.pl:
use hot_web;

use strict;

my $hot = new hot_web;
$hot->count("www.yahoo.com","200"); #set to 200
$hot->count("www.yahoo.com","+20"); #add 200
$hot->count("www.yahoo.com"); #increase by 1
$hot->count("www.google.com","3000"); #set 20 3000
$hot->count("www.google.com","+300"); #add 300
$hot->display;

hot_web.pm:
package hot_web;

use strict;

sub new {
    my $self = {};
    bless $self;
    return $self;
}

sub count {
    my $self = shift;
    my $url = shift;
    if (@_) {
        my $count = shift;
        if ($count =~ /^\+/) {
            $self->{$url} += $count;
        } else {
            $self->{$url} = $count;
        }    
    } else {
        $self->{$url} ++;
    }
}

sub display {
    my $self = shift;
    print "Hot Webs:\n";
    foreach (sort {$self->{$a} < $self->{$b}} keys %{$self}) {
        print "$_ appears: $self->{$_} time(s)\n";
    }
}

1;
[download]

Comment on Re: count sort & output Download Code

Replies are listed 'Best First'.
Re: Re: count sort & output by jdporter (Paladin) on Dec 19, 2002 at 03:29 UTC
`if (defined($hash{$key}) { $hash{$key} ++; } else { $hash{$key} = 1; }` [download] That's actually more work than necessary. All you need is `$hash{$key}++;` because if the element doesn't yet exist, it will be created and initialized ("autovivified") to undef, then the undef will be nummified to 0, then the 0 will be incremented to 1. `%hash = ("www.yahoo.com", 10, "www.google.com", 2000); foreach (keys %hash) { $rev_hash{$hash{$_}} = $_; } foreach (sort keys %rev_hash) { print "$rev_hash{$_} appears: $_ time(s)\n"; }` [download] No, that's bad. What if both yahoo and google have a value of 100? All you're really trying to do it print out the entries sorted by value, numerically. (And, btw, you were sorting lexically, which is also wrong.) `%hash = ( www.yahoo.com => 10, www.google.com => 2000, ); for ( sort { $hash{$a} <=> $hash{$b} } keys %hash ) { print "$_ appears: $hash{$_} time(s)\n"; }` [download] jdporter ...porque es dificil estar guapo y blanco.	[reply] [d/l] [select]
Re^2: count sort & output by Aristotle (Chancellor) on Dec 19, 2002 at 08:39 UTC
I don't want to put down the effort you put into this, but using OO for this a task seems like overkill. How is `$hot->count("www.yahoo.com","200"); #set to 200 $hot->count("www.yahoo.com","+20"); #add 200 $hot->count("www.yahoo.com"); #increase by 1` [download] any better than a hash? `$hot{"www.yahoo.com"} = 200; $hot{"www.yahoo.com"} += 20; $hot{"www.yahoo.com"}++` [download] Note also how the latter makes it immediately obvious what's going on - you don't have to look up a classes' behaviour to know what it does. Lastly, if I did take the OO route for some reason - maybe because I need to pass this around a lot of places in my program, and maybe it does a lot more on-the-fly calculation than just counting mentions, or something - I'd prefer an interface like this: `$hot->count("www.yahoo.com")->set(200); $hot->count("www.yahoo.com")->add(20); $hot->count("www.yahoo.com")->inc;` [download] Makeshifts last the longest.	[reply] [d/l] [select]