Concatenating Non-Redundant Elements into an Array

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

Dear Masters,
With code below I intend to concatenate the array ($aref1 and $aref2) sequentially and intercepted with certain values in between.

use Data::Dumper;
$Data::Dumper::Indent = 0;

my $aref1 = [
              'D 4',
              'E 6'
              ];
my $aref2 = [
             'A 0',
             'B 1',
             'C 2',
             'A 3',
             'B 4'
             ];

my $slen = 5;

concat($aref1,$slen);  # This already give correct result
concat($aref2,$slen);  # This still incorrect

sub concat
{
    my  ($aref,$slen)= @_;

    my @concat;
    foreach  my $i ( 1 ..  $#{$aref} )
    {
        my @out =  split (" ", $aref->[$i-1]);
        my @in  =  split (" ", $aref->[$i]);

        # value to be put in (intercepted)
        my $val = $in[1]-$out[1]-$slen;     

        push @concat, ($out[0],$val,$in[0]);
    }

    print Dumper \@concat ;

    return ;
}
[download]

Currently, only $aref2 still gives incorrect result as follows:

$VAR1 = ['A',-4,'B','B',-4,'C','C',-4,'A','A',-4,'B'];
[download]

As you can see, the result above still contain the 'redundant' elements like B-B, C-C, A-A.
How can I change my code above so that it gives the following correct expected results:

$VAR1 = ['D',-3,'E'];  # from $aref1
$VAR1 = ['A',-4,'B',-4,'C',-4,'A',-4,'B']; # from $aref2
[download]

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

Comment on Concatenating Non-Redundant Elements into an Array Select or Download Code

Replies are listed 'Best First'.
Re: Concatenating Non-Redundant Elements into an Array by Perl Mouse (Chaplain) on Oct 12, 2005 at 09:24 UTC
By not pushing `$in[0]` on the @concat array. And to add an extra push after the loop: `sub concat { my ($aref,$slen)= @_; my @concat; foreach my $i ( 1 .. $#{$aref} ) { my @out = split (" ", $aref->[$i-1]); my @in = split (" ", $aref->[$i]); # value to be put in (intercepted) my $val = $in[1]-$out[1]-$slen; push @concat, ($out[0],$val); } push @concat, ($aref->[-1]=~/\S+/g)[0]; print Dumper \@concat ; return ; }` [download] `Perl --((8:>*`	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re: Concatenating Non-Redundant Elements into an Array
by Perl Mouse (Chaplain) on Oct 12, 2005 at 09:24 UTC

$in[0]

sub concat
{
    my  ($aref,$slen)= @_;

    my @concat;
    foreach  my $i ( 1 ..  $#{$aref} )
    {
        my @out =  split (" ", $aref->[$i-1]);
        my @in  =  split (" ", $aref->[$i]);

        # value to be put in (intercepted)
        my $val = $in[1]-$out[1]-$slen;

        push @concat, ($out[0],$val);
    }
    push @concat, ($aref->[-1]=~/\S+/g)[0];

    print Dumper \@concat ;

    return ;
}
[download]

Perl --((8:>*

[reply]
[d/l]
[select]