[SOLVED]How to sort the referencese

baxy77bax has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

well I'm trying to write a program that needs to sort the suffixes of an array. Let A be an array of characters:


@A = (A,C,D,D,C,D,A,G,F);
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now to sort the suffixes I would naively brake and array into 9 suffix arrays and the sort them out and get something like this:

 
ACDD...
AGF
CDA...
CDD...
DAG...
....


now, how do i do this without chopping thees into sub-arrays, and just do it via references like in c, where you do this through pointers (references).


thnx
baxy


UPDATE:

well thnx ppl for the quick help but there is still a problem that i was not aware of ..... so in the following code i get a strange solution:


 #!/usr/bin/perl

use strict;


my @array = qw(a c a a a c a t a t z);

my @sorted = sort { $array[$a] cmp $array[$b] } (0 .. $#array);

print join('',@array[$sorted[$_] .. $#array]) . "\n" for 0..10;


#prints
acaaacatatz
aaacatatz
aacatatz
acatatz
atatz
atz
caaacatatz
catatz
tatz
tz
z
[download]


isn't "acaaacatatz" lexicographically lower then "aacatatz" ???????(SOLVED : see the code below)

Oh , I just saw your other comments , so what i'm playing arround is Kasai's algorithm so the whole code is : ---


UPDATE2 : all corrected and below is the working code if anyone needs is, it is a bit naive but illustrates the point and it works 

Code was moved to :
Kasai's algorithm


so if someone is looking for it, well here it is , in Perl !!!!
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Re: How to sort the referencese by johngg (Canon) on Aug 10, 2011 at 10:00 UTC
Your question is a little unclear but my guess from your partial output is that you want something like this. `use strict; use warnings; use 5.010; my @arr = qw{ A C D D C D A G F }; my $str = join q{}, @arr; say for sort map { substr $str, $_ } 0 .. length( $str ) - 1;` [download] The output. `ACDDCDAGF AGF CDAGF CDDCDAGF DAGF DCDAGF DDCDAGF F GF` [download] I hope I have guessed correctly and that this is helpful. Update: A version that works on array subscripts rather than offsets into a joined string, using the revised data in the OP. `use strict; use warnings; use 5.010; my @arr = qw{ a c a a a c a t a t z }; my @sortedIndices = map { $_->[ 0 ] } sort { $a->[ 1 ] cmp $b->[ 1 ] } map { [ $_, join q{}, @arr[ $_ .. $#arr ] ] } 0 .. $#arr; say join q{}, @arr[ $sortedIndices[ $_ ] .. $#arr ] for 0 .. $#sortedIndices;` [download] Outputs `aaacatatz aacatatz acaaacatatz acatatz atatz atz caaacatatz catatz tatz tz z` [download] Cheers, JohnGG	[reply] [d/l] [select]
Re: How to sort the referencese by jethro (Monsignor) on Aug 10, 2011 at 09:14 UTC
You can't do the same thing as in C. But you can create a second array with the sorted indices: `my @A = qw(A C D D C D A G F); my @sorted = sort { $A[$a] cmp $A[$b] } (0 .. $#A); print @sorted,"\n"; print @A[$sorted[1] .. $#A],"\n"; print @A[$sorted[4] .. $#A],"\n"; # prints 061423587 AGF DDCDAGF` [download]	[reply] [d/l]
Re: How to sort the referencese by Utilitarian (Vicar) on Aug 10, 2011 at 09:07 UTC
Hi baxy, I think you're looking for array slices `print "Good ",qw(night morning afternoon evening)[(localtime)[2]/6]," fellow monks."`	[reply] [d/l]