sorting difficulty

texuser74 has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,

I want to sort the attribute values inside <tag refid="5,8,7,3,2,1"> and remove the commas.

i.e. input: <tag refid="5,8,7,3,2,1"> some other text
output: <tag refid="1 2 3 5 7 8"> some other text

test.txt:
<tag refid="5,8,7,3,2,1"> some other text

open(IN, "<test.txt") || die "\nCan't open test.txt \n";
$/="";
{
   local $/ = '<tag refid="';
   print OUT scalar <IN>;
   for (<IN>) {
      s@(.*?)">@
      my $var = $1;
      $var @e;
      print "$_\n" for sort { $a cmp $b } split /,/;
   }
}
close(IN);
close(OUT);
[download]

but my present code is printing wrong with extra text.

1 some other text

2
3
5
7
8
[download]

Pls help me in correcting this.

Comment on sorting difficulty Select or Download Code

Replies are listed 'Best First'.
Re: sorting difficulty by moritz (Cardinal) on May 07, 2008 at 09:59 UTC
`use strict; use warnings; my $str = q{<tag refid="5,8,7,3,2,1">}; sub sort_and_reformat { my $s = shift; return join " ", sort split m/,/, $s; } $str =~ s/"([^"])"/'"' . sort_and_reformat($1) . '"'/eg; print $str, $/;` [download] The regex isn't very selective about what it considers an attribute, so you might want to tweak that. Update: You can use look-ahead and -behind to get rid of that ugly substitution body: `$str =~ s/(?<=")([^"])(?=")/sort_and_reformat($1)/eg;` [download] If you want to be more specific about what to match, you can use something like this: `$str =~ s/(?<=<tag refid=")([^"]*)(?=")/sort_and_reformat($1)/eg;` [download]	[reply] [d/l] [select]
Re^2: sorting difficulty by texuser74 (Monk) on May 07, 2008 at 10:22 UTC
hi, thanks for your reply. `$str =~ s/(?<=<tag refid=")([^"]*)(?=")/sort_and_reformat($1)/eg;` is not removing commas. also, 1 more doubt, some times i might need to sort alphabets too, e.g. `<tag refid="c,b,a">`	[reply] [d/l] [select]
Re^3: sorting difficulty by moritz (Cardinal) on May 07, 2008 at 10:26 UTC
is not removing commas. Did you even try it? It works for me. If it really doesn't work for you: What version of perl are you using, and what's the result on your perl? If you want to sort both numbers and letters correctly, you should use Sort::Naturally (and replace `sort` with `nsort`).	[reply] [d/l] [select]
Re^4: sorting difficulty by texuser74 (Monk) on May 07, 2008 at 10:31 UTC
Re: sorting difficulty by jwkrahn (Abbot) on May 07, 2008 at 10:14 UTC
$ echo ' Dear Monks, I want to sort the attribute values inside <tag refid="5,8,7,3,2,1"> a +nd remove the commas. i.e. input: <tag refid="5,8,7,3,2,1"> some other text output: <tag refid="1 2 3 5 7 8"> some other text test.txt: <tag refid="5,8,7,3,2,1"> some other text ' \| perl -e' $/ = ">"; while ( <> ) { s{(<tag refid=")([0-9,]+)(">)\z}{$1@{[ sort { $a <=> $b } $2 =~ /\ +d+/g ]}$3}; print; } ' Dear Monks, I want to sort the attribute values inside <tag refid="1 2 3 5 7 8"> a +nd remove the commas. i.e. input: <tag refid="1 2 3 5 7 8"> some other text output: <tag refid="1 2 3 5 7 8"> some other text test.txt: <tag refid="1 2 3 5 7 8"> some other text [download]	[reply] [d/l]