Re^2: Limit the size of a hash

I just wrote my own with insertion sort. Looks like you beat me to it. This one no longer needs to initialise and sort the store array with real data, it just fills it with the correct number of zero values.

use strict; 
use warnings; 
use Data::Dumper;

my $keep = 5;
my @keeper;
push @keeper, [0] for 1 .. $keep;

while (<DATA>) {
    my @vals  = split;
    next unless @vals; # possibly more sophisticated test
    my $score = pop @vals;
    addlist ([$score, \@vals], \@keeper);
}

print Dumper \@keeper;

# slide up the list knocking down existing records
# until we no longer have the biggest
sub addlist {
    my ($rec, $list) = @_;
    for my $i (0 .. $#$list) {
        if ($rec->[0] > $list->[$i]->[0]) {
            $list->[$i-1] = $list->[$i] if $i;
            $list->[$i]   = $rec;
        }
        else {
            last;
        }
    }
}

__DATA__
0 5 3 7   0.97
1 3 4 8   0.18
1 4 4 8   0.21
1 7 4 4   0.22
1 8 4 8   0.52
1 9 4 1   0.16
1 5 1 8   0.18
1 5 2 9   0.72
1 5 5 8   0.32
1 5 6 6   0.17
1 5 7 4   0.52
1 5 9 3   0.92
1 5 4 8   0.99
6 8 4 6   0.54
[download]

Cheers,
R.

Pereant, qui ante nos nostra dixerunt!

Comment on Re^2: Limit the size of a hash Download Code

Replies are listed 'Best First'.
Re^3: Limit the size of a hash by hdb (Monsignor) on Sep 05, 2013 at 14:16 UTC
I am usually careful with default values. Here you implicitely assume that all scores are positive, otherwise the zeroes could influence the result...	[reply]
Re^4: Limit the size of a hash by Random_Walk (Prior) on Sep 06, 2013 at 10:21 UTC
Good point. Here is a better version that does not have to define this list first and does not make any assumptions about the size values. #!/usr/bin/perl use strict; use warnings; use Data::Dumper; my $keep = 5; my @keeper; while (<DATA>) { my @vals = split; next unless @vals; # possibly more sophisticated test my $score = pop @vals; addlist ([$score, \@vals], \@keeper); } print Dumper \@keeper; # slide up the list knocking down existing records # until we no longer have the biggest sub addlist { my ($rec, $list) = @_; for my $i (0 .. $keep-1) { if (not $list->[$i] or $rec->[0] > $list->[$i]->[0]) { $list->[$i-1] = $list->[$i] if $i; $list->[$i] = $rec; } else { last; } } } __DATA__ 0 5 3 7 0.97 1 3 4 8 0.18 1 4 4 8 0.21 1 7 4 4 0.22 1 8 4 8 0.52 1 9 4 1 0.16 1 5 1 8 0.18 1 5 2 9 0.72 1 5 5 8 0.32 1 5 6 6 0.17 1 5 7 4 0.52 1 5 9 3 0.92 1 5 4 8 0.99 6 8 4 6 0.54 [download] Cheers, R. Pereant, qui ante nos nostra dixerunt!	[reply] [d/l]