Instead of using "parallel" data structures that have to be handled piecemeal, group common data using a hash

But that uses more memory. Which can be significant if you have a lot of data. 

#!/usr/bin/perl

use 5.010;

use strict;
use warnings;

use Devel::Size qw [total_size];

my $size = 250_000;

my @fields = qw [chr start end symbol strand];
my %families;
my @structs = \my (%chr, %start, %end, %symbol, %strand);

foreach my $key (1 .. $size) {
    $families{$key}{$_} = undef for @fields;  
    $$_{$key} = undef for @structs; 
}

my $s1 = total_size \%families; 
my $s2 = 0; 
   $s2 += total_size $_ for @structs;

printf "Big hash: %d Mb\n", $s1 / (1024 * 1024);
printf "More hashes: %d Mb\n", $s2 / (1024 * 1024);
printf "Savings: %.0f%%\n", 100 * ($s1 - $s2) / $s1;

__END__
Big hash: 71 Mb
More hashes: 61 Mb
Savings: 14%

[download]
Grouping the data in a hash causes you to have 1250001 hashes, instead of just 5. Which carries a 10 Mb penalty.

In reply to Re^2: If Statements and Regular Expressions by JavaFan
in thread If Statements and Regular Expressions by TempAcolyte

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.