#!/usr/bin/perl

# Program name: next-value-of-hash.pl  Run it, thusly: perl next-value
+-of-hash.pl  Look at the next value of hash when sorting by values

# From perlmonks Chatterbox 20170213 reply by [ambrus]

# [stu96art]    I am hoping to get some help with hashes. Working on l
+ooking at the next value when sorting by values, but don't know how t
+o reference it.
# [stu96art]    My code is on my scratchpad: /padstu96art
# [ambrus]    stu96art: perhaps try to first assign the sorted key lis
+t to an array variable, then iterate through that array with indexes
# [stu96art]    Gotcha. That makes sense. Appreciate the help.
# [ambrus]    like my@s = sort keys %a; for my$i (keys@s) { print "cur
+rent: $s[$i] => $a{$s[$i]}, next: ", ($i+1<@s ? "$s[$i+1] => $a{$s[$i
++1]}" : "none"); }
# [stu96art]    Thanks again. I will work on that.

use strict;
use warnings;

# Example hash from https://perlmaven.com/perl-hashes

my %color_of = (
    "apple",  "red",
    "orange", "orange",
    "grape",  "purple",
    "tomato",  "red",
    "lettuce",  "green",
    "peanut",  "tan",
);

my @s = sort keys %color_of;
for my $i ( keys @s ) {
    print "current: $s[$i] => $color_of{$s[$i]}, next: ",
      ( $i + 1 < @s ? "$s[$i+1] => $color_of{$s[$i+1]}" : "none" );
    print "\n";
}

__END__

[download]

Close readers will note the following: stu96art specified "when sorting by values".

It is debatable whether he meant Sort the values of the hash or Sort the hash in alphabetical order of its keys.

https://perlmaven.com/how-to-sort-a-hash-in-perl is a good place to start to learn this particular subject.

In reply to Look at the next value of hash when sorting by values by Cow1337killr

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.