What did you try so far? Have you looked at Perls sort function? The documentation is available via perldoc -f sort, or perldoc sort. Did you try simply using sort? Please don't ask us to do your homework!

The sort documentation mentions the following example:

@articles = sort {$a cmp $b} @files;
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Maybe you can adapt it to your needs.

This answer is intentionaly vague since your data changed twice and I have no idea which to use, and it appears this is some sort of homework because of the strange no split suggestion. If you can't use split, then look for some way to split a string without using split. One way would be to use substr instead.

my $test = "Hello World";
my $new  = substr($test, 6,5) . "-" . substr($test,0,5);
print $new;
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I wanto sort @list. But without using any Date Sort modules. But we I can use perl's sort function.

How that can be done.

NOTE:

Please don't use split also.

Use Time::Local to convert the dates to 'seconds since epoch' values, sort them, then use localtime or gmtime to convert back to a human-readable format. This assumes you want the dates sorted chronologically, and not by month or day number...

Or does that count as a 'Date Sort' module? ;-)

The solution will probably involve sorting the YYYY-MM-DD elements alphabetically (which works out to chronologically in this case), mapping each element of the sorted list to a hash where the value is the date's index position in the sorted list. But at that point you'll have to use split to reformat the original strings before pushing them onto a new list in an order specified by the hash, which you will be using as a look-up table.

So I don't understand why you're forbidden to use split as part of the solution. Please clarify.

Jim Keenan

But at that point you'll have to use split to reformat the original strings before pushing them onto a new list in an order specified by the hash, which you will be using as a look-up table.

Well, split is indeed the most natural tool to do that, and the one I would use, and to stress it once more: there's really no good reason why one should not use it! (or else the OP should provide one!) But as usual TMTWOTDI: see for example the alternative I offer in this reply - it's even actually shorter...

I can understand that in some companies you are not allowed to install any odd module on your system, but not using a built-in function? It is like saying: "please add this list of figures but don't use +!"

No + or =

sub add_em {
    my $sum;
    for (@_) {
        for (1..$_) {
          $sum--;
        }
    }
    return -$sum;
}
print add_em(1..5);
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Sorry just couldn't resist ;)


___________
Eric Hodges

No +, - or =:

print sum(1..10);

sub sum {
    return scalar map { 1..$_ } @_
}
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---

s$$([},&%#}/&/]+}%&{})*;#$&&s&&$^X.($'^"%]=\&(|?*{%
+.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e

Date::Sort::Split

Keep pouring your ideas - but not out loud

;-)

I wanto sort @list. But without using any Date Sort modules. But we I can use perl's sort function.

Please don't use split also.

WTF?

Why the restrictions? What are you really trying to accomplish here?

Looking at your posts you're not even consistant with the format of the dates in question...

Read the doco for the sort function and take a look at the ability to define a function that sort will use to do its thing. Give that a try and come back to us and show us some code.

"Keep pouring your ideas"

Everybody has to believe something... I believe I'll pour another beer....

use strict;

# use schwartzian transform if the size is big
my @dates1 = ( '05-11-2006', '01-01-2005' , '04-12-2005' , '22-03-2005
+');
@dates1 = sort{substr($a,6,4)<=>substr($b,6,4)||substr($a,3,2) <=>subs
+tr($b,3,2)||substr($a,0,2)<=>substr($b,0,2)}@dates1;
print join("\n",@dates1);

print "\n\n";

# this format is easy, it's just alpha-numeric
my @dates2 = ( '2005-12-01' , '2005-11-02' , '2005-12-07'); 
my @dates2 = sort @dates2;
print join("\n",@dates2);

__OUTPUT__
01-01-2005
22-03-2005
04-12-2005
05-11-2006

2005-11-02
2005-12-01
2005-12-07
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my @list = ('2005-12-01', '2005-11-02', '2005-12-07');
@list = sort @list;
print join "\n", @list;
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@list = reverse sort @list;
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use strict;
use warnings;

my @sort = ('05-11-2006', '01-01-2005', '04-12-2005', '22-03-2005');

@sort =
    map { join '-', reverse split /-/ }
    sort
    map { join '-', reverse split /-/ }
@sort;

print join "\n", @sort;
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I wanto sort @list. But without using any Date Sort modules. But we I can use perl's sort function.

I find this mostly annoying. Every now and again someone pops up and asks "how can I do XYZ without using any module?" In most cases this is plainly stupid - check e.g. this quotation, and is being asked because the person who asks does not have root privileges and ignores that modules can be installed locally too. See for example this section of the Tutorials.

In this case your post may suggest you're asking about homework instead, which is also advised against here. Personally I don't find anything wrong with it, provided that you clearly state so and you show what you've tried, so that we do not give ready-made solutions, which most of us won't do in any case -because we're not a helpdesk- and help you to learn instead.

Please don't use split also.

This also smells too much like homework, which I don't like. Indeed, if you have your numbers e.g. in a "MM-DD-YYYY" format as some of your post seem to imply, then it is quite natural to get individual chunks to sort upon like thus:

my ($m, $d, $y) = split /-/;
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you don't like it? Then

my ($m, $d, $y) = /\d+/g;
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will work just the same if you trust the format of your dates. Now, is this acceptable for your teacher?

use strict;
use warnings;

my @list = ( '2005-12-01' , '2005-11-02' , '2005-12-07');

my @sorted = map  { $_->[3] }
             sort {
                     $a->[0] <=> $b->[0]  ||
                     $a->[1] <=> $b->[1]  ||
                     $a->[2] <=> $b->[2]
                  }
             map  {
                    [ 
                      unpack( 'A4 x[A] A2 x[A] A2', $_ ),
                      $_ 
                    ]
                  }
             @list;
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Your restrictions are beyond baffling.

$ perl -le 'print for sort qw/2005-12-01 2005-11-02 2005-12-07/'
2005-11-02
2005-12-01
2005-12-07
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