Removal of duplicated element in array.

tty1x has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Removal of duplicated element in array. by moritz (Cardinal) on May 06, 2013 at 14:01 UTC
How exactly does it not work? What exactly is in `$1`? What output do you expect? Are you aware that the code as-is splits on newline characters, which means that "duplicate items" actually mean "duplicate lines"? If you want to deduplicate a list, I recommend List::MoreUtils::uniq. Perl 6 - the future is here, just unevenly distributed	[reply] [d/l]
Re^2: Removal of duplicated element in array. by tty1x (Novice) on May 06, 2013 at 14:10 UTC
$1 is essentially a list of email addresses. dddd@fgg.com cccc@fgg.com eeee@fgg.com dddd@fgg.com	[reply]
Re^3: Removal of duplicated element in array. by 2teez (Vicar) on May 06, 2013 at 14:15 UTC
`my %seen = map {$_=>1} <DATA>; use Data::Dumper; print Dumper \%seen; __DATA__ dddd@fgg.com cccc@fgg.com eeee@fgg.com dddd@fgg.com` [download] UPDATE: If you care about the order of display then you can use this: `print join "\n", sort{$a cmp $b} keys %seen;` Note: That was based on the assumption, that the original `ORDER` of data was inconsequential. Limbic~Region Thanks for pointing that out. If you tell me, I'll forget. If you show me, I'll remember. if you involve me, I'll understand. --- Author unknown to me	[reply] [d/l] [select]
Re^4: Removal of duplicated element in array. by Limbic~Region (Chancellor) on May 06, 2013 at 18:11 UTC
Re^5: Removal of duplicated element in array. by 2teez (Vicar) on May 06, 2013 at 21:40 UTC
Re: Removal of duplicated element in array. by 2teez (Vicar) on May 06, 2013 at 14:07 UTC
Check How can I remove duplicate elements from a list or array? If you tell me, I'll forget. If you show me, I'll remember. if you involve me, I'll understand. --- Author unknown to me	[reply]
Re^2: Removal of duplicated element in array. by Rahul6990 (Beadle) on May 06, 2013 at 14:11 UTC
Thanks for sharing , the link has very useful stuff.	[reply]
Re: Removal of duplicated element in array. by hdb (Monsignor) on May 06, 2013 at 14:20 UTC
One issue are the parantheses in `split("(\n)",$match)`. They preserve the delimiters \n as part of your array and are also present in the final result @r. Try `split /\n/, $match` [download] instead. You can also do it as a one-liner: `my @r = keys { map { $_ => 1 } split /\n/, $match };` [download] UPDATE: I mean the parantheses in `"(\n)"`, not the outer ones.	[reply] [d/l] [select]
Re^2: Removal of duplicated element in array. by tty1x (Novice) on May 06, 2013 at 14:54 UTC
I tried `my @match_to_array = split (/\n/,$match);` , the `\n` are not preserved. `my @r = keys { map { $_ => 1 } split /\n/, $match };` has " Type of arg 1to keys must be hash (not annonymous hash ) " error. Guess I did something wrong for the -rep ? Sorry If I did so.	[reply] [d/l] [select]
Re^3: Removal of duplicated element in array. by hdb (Monsignor) on May 06, 2013 at 15:02 UTC
Might be that you are using an older version of Perl? I'm on 5.16. Here is a two line version: `my %seen = map { $_ => 1 } split /\n/, $match; my @r = keys %seen;` [download] Hope this now works for you. And I still assume that you want to get rid of the \n? Apologies for any confusion I caused.	[reply] [d/l]
Re^4: Removal of duplicated element in array. by tty1x (Novice) on May 07, 2013 at 02:19 UTC
Re^2: Removal of duplicated element in array. by tty1x (Novice) on May 06, 2013 at 14:36 UTC
`/\n/` doesn't preserve the delimiters =X .	[reply] [d/l]
Re: Removal of duplicated element in array. by Rahul6990 (Beadle) on May 06, 2013 at 14:05 UTC
Hi, For me the same code is working `my @match_to_array = (a,b,c,a,d,c,b,r); my %seen = (); my @r = (); foreach my $a (@match_to_array) { unless ($seen{$a}) { push @r, $a; $seen{$a}++; } } print "@r"; print "\n@match_to_array";` [download] Can you explain how it is not working , with actual and expected output.	[reply] [d/l]
Re^2: Removal of duplicated element in array. by 2teez (Vicar) on May 06, 2013 at 14:36 UTC
Hi Rahul6990 , this line :`my @match_to_array = (a,b,c,a,d,c,b,r); #Oops` should either be `my @match_to_array = ('a','b','c','a','d','c','b','r');` OR `my @match_to_array = qw(a b c a d c b r);` If you tell me, I'll forget. If you show me, I'll remember. if you involve me, I'll understand. --- Author unknown to me	[reply] [d/l] [select]
Re^2: Removal of duplicated element in array. by tty1x (Novice) on May 06, 2013 at 14:16 UTC
dddd@fgg.com cccc@fgg.com eeee@fgg.com dddd@fgg.com The above is both the input and output. The output is still the same after running the code.	[reply]
Re: Removal of duplicated element in array. by Laurent_R (Canon) on May 06, 2013 at 18:44 UTC
As I already told you on another forum, the problem is most probably in the split. Try this instead: `my @match_to_array = split /\n/, $match;`	[reply] [d/l]
Re^2: Removal of duplicated element in array. by tty1x (Novice) on May 07, 2013 at 02:13 UTC
I tried what you mentioned, it still didn't work. I also tried totally eliminating the split operator altogether, and directly assign the $match to the @match_to_array , it didn't work too.	[reply]
Re: Removal of duplicated element in array. by 2teez (Vicar) on May 07, 2013 at 04:25 UTC
Hi tty1x, A few snapshot observations and 2 'kobo' suggestion: A number of solution previously given to you actually work, only that some may not preserve the order of data. This does work for me, which is not far from your OP, except that I have to create the variable $match. `use warnings; use strict; my $match = <<'EOF'; dddd@fgg.com cccc@fgg.com eeee@fgg.com dddd@fgg.com EOF my %seen; my @r; foreach my $v ( split /\n/, $match ) { unless ( $seen{$v}++ ) { push @r, $v; } } $" = "\n"; print "@r";` [download] Please, as much as possible try not to use the variable $a, since function sort uses it Tested this out on codepad an online compiler/interpreter. If you tell me, I'll forget. If you show me, I'll remember. if you involve me, I'll understand. --- Author unknown to me	[reply] [d/l]
Re^2: Removal of duplicated element in array. by choroba (Cardinal) on May 07, 2013 at 15:12 UTC
Perl 5.8.0? What a pitty :-( لսႽ� ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply]
Re^3: Removal of duplicated element in array. by 2teez (Vicar) on May 07, 2013 at 16:29 UTC
Yeap! I know. When the OP kept complaining about virtually all the solution given and he/she said he/she is using v5.10.1. I thought if the solution am presenting works on a version as old as v5.8.0, then it should work on v5.10.1. That was why I mentioned that. If you tell me, I'll forget. If you show me, I'll remember. if you involve me, I'll understand. --- Author unknown to me	[reply]
Re: Removal of duplicated element in array. by Laurent_R (Canon) on May 07, 2013 at 09:28 UTC
Hi, I do not know what you changed, but taking your original program, changing the split pattern to /\n/ (and adding a few prints just to show the content of the various variables) show that this works perfectly. `my $match = "foo1\nfoo2\nfoo3\nfoo4\nfoo5\nfoo3\nfoo2"; print '$match = ', "\n", $match, "\n\n"; my @match_to_array = split /\n/, $match; print '@match_to_array = ', "@match_to_array \n\n"; my %seen = (); my @r = (); foreach my $a (@match_to_array) { unless ($seen{$a}) { push @r, $a; $seen{$a}++; } } print '@r = ', "@r";` [download] This is now the output: `$ perl remove_duplicates.pl $match = foo1 foo2 foo3 foo4 foo5 foo3 foo2 @match_to_array = foo1 foo2 foo3 foo4 foo5 foo3 foo2 @r = foo1 foo2 foo3 foo4 foo5` [download] The duplicate values (foo3 and foo2) have been duly removed.	[reply] [d/l] [select]
Re^2: Removal of duplicated element in array. by Laurent_R (Canon) on May 07, 2013 at 17:52 UTC
The problem is simply that the OP is making the suggested corrections on a piece of code that is different from what he has presented (as he has admitted in his cross-post on a different forum). @ tty1x: we cannot guess what other bugs you have in your code if you don't tell us what this code is.	[reply]