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

Dear Masters,

How can I modify my code below. Such that given $tpl, I can remove the recurring consecutive alphabet,
B-B into just B, and A-A into just A?

Is there a better way to implement it?
Also could it be made faster?
My current wrong answer and the intended result is shown below.
Update: Typo corrected. Thanks to skillet-thief . 
use Data::Dumper;

my $tpl = ['A -4 B','B -4 C','C -4 A','A -4 B'];
get_alphb_fr_tpl($tpl);

sub get_alphb_fr_tpl
{
  my $aref = shift;
  my @str  = grep (!/[\d+\s+]/,map{ split " ",$_} @{$aref}) ;
  print Dumper \@str ;
  return;
}

[download]
Such that it gives: 
$VAR1 = ['A','B','C','A','B'];

[download]
Instead of: 
$VAR1 = ['A','B','B','C','C','A','A','B'];

[download]


---
neversaint and everlastingly indebted.......

Replies are listed 'Best First'.
Re: Removing recurring consecutive element
by Skeeve (Parson) on Oct 13, 2005 at 07:06 UTC

    Hmmm... Sure you want to delete consecutive same elements? To me it seems you want the first word of each string.

    If so what about: 

    my @str  = map{ (split ' ', $_, 2)[0] } @{$tpl} ;

    [download]

    instead of your grep-line

    This way you get the first element of each of your strings.

    s$$([},&%#}/&/]+}%&{})*;#$&&s&&$^X.($'^"%]=\&(|?*{%
    +.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e
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[d/l]
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      To me it seems you want the first word of each string.
      No Skeeve. That's not what I want. Instead of this: 
      $VAR1 = ['A','B','C','A'];

      [download]
      I am looking for this: 
      $VAR1 = ['A','B','C','A','B'];

      [download]
      So you can see. For the last array I want to keep the 'last word', which is B. I hope that's clearer for you now.

      ---
      neversaint and everlastingly indebted.......
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        If that's what you want. Add this one line after Skeeve's. 
           push @str, (split ' ',$tpl->[-1])[2];

        [download]
        Sorry I still don't know if this implementation gives the fastest running time.

        Regards,
        Edward
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[d/l]
Re: Removing recurring consecutive element
by neosamuri (Friar) on Oct 13, 2005 at 07:20 UTC
    You could do something like this:
    sub get_alphb_fr_tpl
{
  my $aref = shift;
  my @str  = grep (!/[\d+\s+]/,map{ split " ",$_} @{$tpl}) ;
  my $lst = '';
  my @out;
  for(@str){
     $out[@out] = $_ unless $lst eq $_;
     $lst = $_;
  }
  print Dumper \@out ;
  return;
}

    [download]
    I am sure that there is a more elegant way of doing it, but this works.
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[d/l]
Re: Removing recurring consecutive element
by skillet-thief (Friar) on Oct 13, 2005 at 07:30 UTC

    I assume it is a typo, but you are not using the $aref that you are passing to the sub, and instead working directly on $tpl.

    s-t

    sub sk{ return unless $in = shift;
        $in =~ s!(.)$!!; print $1; sk($in)}
sk("gro.alubaf@yehaf");

    [download]
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[d/l]
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Re: Removing recurring consecutive element
by Perl Mouse (Chaplain) on Oct 13, 2005 at 08:53 UTC
[reply]

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