Here is my "go" at this (below)....The problem statement is tough and requires some strange looking code.

The data is read into an AoA and also the "ordinal" number before the combination of the "name and code" is also read into a hash table, a HoA with ordinal numbers. "ordinal number" here is a misnomer and is an artifact of first approach to the code. I expect the OP to rename things.

As it turns out, only the combination of the name and code at the end of line is unique. flintoff has JJ113952 and peter also has JJ113952.

The ordinal numbers for each combination of name/code are sorted. I also showed how to sort the original DB with a "weird sort order", but I'm not sure this is necessary and of course this can be modified to get all kinds of orders.

To print the data, if the name/code como is unique, this is a singleton. To print "end" token, there are "gaps" in what I called the ordinal numbers, so I use the maximum one what was seen. This is the -1 index. 

#!/usr/bin/perl -w
use strict;
use Data::Dumper;

my @DB;
my %hash;

while (<DATA>)
{
  my($n1,$n2,$letter,$ordinal,$name,$code) = 
              (my @record = split(/[\s,]+/,$_));
  push (@DB, [@record]);
  push (@{$hash{"$name$code"}},$ordinal);
}

foreach my $name_code (keys %hash)
{
  @{$hash{$name_code}}= sort{$a<=>$b} @{$hash{$name_code}};
}

@DB = sort by_weird_sort_order @DB; #optional sort

foreach my $line (@DB)
{
   my($n1,$n2,$letter,$ordinal,$name,$code) = @$line;
   $ordinal = "single" if @{$hash{"$name$code"}} == 1;
   $ordinal = "end" 
                 if (     @{$hash{"$name$code"}}>1 
                   and (@{$hash{"$name$code"}})[-1] == $ordinal
                    );
   printf STDOUT ("%-7s %-7s %-3s %s,%s,%s\n",
                 $n1,$n2,$letter,$ordinal,$name,$code);
}

sub by_weird_sort_order
{
   my ($a_ordinal,$a_name) = (@$a)[3,4];
   my ($b_ordinal,$b_name) = (@$b)[3,4];
        
         $a_name  cmp $b_name
                  or
        $b_ordinal <=> $a_ordinal                  
}

#PRINTS:
#62556   63635   y   single,andrew,JJ113954
#126185  126699  s   single,austin,JJ113956
#441474  441538  b   end,catherine,JJ029490
#442666  442843  9   8,catherine,JJ029490
#445778  445905  0   7,catherine,JJ029490
#446059  446273  l   6,catherine,JJ029490
#450319  450379  f   5,catherine,JJ029490
#81099   81630   y   single,flintoff,JJ113952
#68766   69005   j   end,morgan,JJ113955
#63868   63897   h   1,morgan,JJ113955
#158146  158367  i   end,peter,JJ113952
#135588  136297  8   2,peter,JJ113952
#135356  135449  3   1,peter,JJ113952

__DATA__
62556    63635    y    1,andrew,JJ113954
63868    63897    h    1,morgan,JJ113955
68766    69005    j    2,morgan,JJ113955
81099    81630    y    1,flintoff,JJ113952
126185    126699    s    1,austin,JJ113956
135356    135449    3    1,peter,JJ113952
135588    136297    8    2,peter,JJ113952
158146    158367    i    3,peter,JJ113952
441474    441538    b    9,catherine,JJ029490
442666    442843    9    8,catherine,JJ029490
445778    445905    0    7,catherine,JJ029490
446059    446273    l    6,catherine,JJ029490
450319    450379    f    5,catherine,JJ029490

[download]

In reply to Re: Tagging the last elements by Marshall
in thread Tagging the last elements by crochunter

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.