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

Hello Monks!
I need to remove one level from this array, can't think how to get it done.
In a nut shell, the original data comes as an example like this:
$VAR1 = [ [ {},... ],[ {},... ]...];

[download]
I need it to be as this:
$VAR1 = [ {},... ],[ {},... ]...;

[download]

Here is the code that shows how I am trying. 
#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my $recs = collect();

print Dumper $rec;

=code
$VAR1 = [
          [
            {
              'YEAR' => '2008',
              'MONTH' => 'MARCH',
              'COLOR_CODE' => '1'
            },
            {
              'YEAR' => '2014',
              'MONTH' => 'APRIL',
              'COLOR_CODE' => '2'
            },
            {
              'YEAR' => '2014',
              'MONTH' => 'DECEMBER',
              'COLOR_CODE' => '3'
            }
          ],
          [
            {
              'YEAR' => '2001',
              'MONTH' => 'MAY',
              'COLOR_CODE' => '1'
            },
            {
              'YEAR' => '2009',
              'MONTH' => 'JUNE',
              'COLOR_CODE' => '2'
            },
            {
              'YEAR' => '2001',
              'MONTH' => 'MAY',
              'COLOR_CODE' => '1'
            },
            {
              'YEAR' => '2009',
              'MONTH' => 'JUNE',
              'COLOR_CODE' => '2'
            },
            {
              'YEAR' => '2013',
              'MONTH' => 'JULY',
              'COLOR_CODE' => '2'
            },
            {
              'YEAR' => '2016',
              'MONTH' => 'SEPTEMBER',
              'COLOR_CODE' => '4'
            }
          ]
        ];
=cut

my @test = ();

foreach my $rec ( @{$recs} ) {
   warn Dumper $rec; # This prints the data structure I am looking for
+:
=code
$VAR1 = [
          {
            'YEAR' => '2008',
            'MONTH' => 'MARCH',
            'COLOR_CODE' => '1'
          },
          {
            'YEAR' => '2014',
            'MONTH' => 'APRIL',
            'COLOR_CODE' => '2'
          },
          {
            'YEAR' => '2014',
            'MONTH' => 'DECEMBER',
            'COLOR_CODE' => '3'
          }
        ];
$VAR1 = [
          {
            'YEAR' => '2001',
            'MONTH' => 'MAY',
            'COLOR_CODE' => '1'
          },
          {
            'YEAR' => '2009',
            'MONTH' => 'JUNE',
            'COLOR_CODE' => '2'
          },
          {
            'YEAR' => '2001',
            'MONTH' => 'MAY',
            'COLOR_CODE' => '1'
          },
          {
            'YEAR' => '2009',
            'MONTH' => 'JUNE',
            'COLOR_CODE' => '2'
          },
          {
            'YEAR' => '2013',
            'MONTH' => 'JULY',
            'COLOR_CODE' => '2'
          },
          {
            'YEAR' => '2016',
            'MONTH' => 'SEPTEMBER',
            'COLOR_CODE' => '4'
          }
        ];
=cut

   push @test, $rec; # The print Dumper  will get the data structure b
+ack to its original format
             # I need it in the structure of the $rec Dumper above.
 }

print Dumper \@test;
# This is what I am trying to get:
=code
$VAR1 = [
          {
            'YEAR' => '2008',
            'MONTH' => 'MARCH',
            'COLOR_CODE' => '1'
          },
      ...
    ];
$VAR1 = [
          {
            'YEAR' => '2001',
            'MONTH' => 'MAY',
            'COLOR_CODE' => '1'
          },
      ...
    ];
=cut

 sub collect {

  ... # <<< data in $more_rec;
  my @all = ();
 foreach my $number ( keys %{$more_rec} ) {
    
   my $numbers = $more_rec->{$numbers};
   push @all, $numbers->{agenda};
   
 }

 return \@all

 }

[download]
Thanks for looking!

Replies are listed 'Best First'.
Re: Remove one level from array
by LanX (Saint) on Oct 28, 2015 at 15:39 UTC
     $a_new = $a_old->[0] ?

    UPDATE

    I'm confused, cause this doesn't really make sense

    > $VAR1 = [ {},... ],[ {},... ]...;

    might be you want:

    @new = @$a_old;

    if not please explain.

    Cheers Rolf
    (addicted to the Perl Programming Language and ☆☆☆☆ :)
    Je suis Charlie!

[reply]
[d/l]
[select]
      That was just to illustrate the data structure, the code sample shows it better.
[reply]
Re: Remove one level from array
by stevieb (Canon) on Oct 28, 2015 at 15:54 UTC

    What you have is an array of arrays of hashes. You can not strip off the outer array, or else you'd be trying to stuff a bunch of array refs into a single scalar, and that won't fly.

    What I think you want to do is simply iterate over the encompassing array and act on each inner aref one at a time:

    my @numbers = collect(@test);

sub collect {

    my @test = @_;
    my @all;

    for my $more_rec (@test){
        for my $number (keys %{ $more_rec }){
            my $numbers = $more_rec->{$number};
            push @all, $numbers->{agenda};
        }
    }

    return @all;
}

    [download]

    However, it's doubly difficult to really understand what you want, because your data examples do not jive with what was in your collect() function. In there, you're extracting an href ($numbers) from within another href ($more_rec), and then from within $numbers, you're extracting the value of the agenda key. None of that is shown in your example data. Also, your collect() has at least one issue. You extract $number from keys(), but then never proceed to use it.

[reply]
[d/l]
[select]
Re: Remove one level from array
by hdb (Monsignor) on Oct 28, 2015 at 15:54 UTC

    How about 

    $VAR1 = [ map { 'ARRAY' eq ref( $_ ) ? @$_ : $_ } @$VAR1 ];

    [download]
[reply]
[d/l]
Re: Remove one level from array
by poj (Abbot) on Oct 28, 2015 at 16:45 UTC
    Try 
    #!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

my $more_rec = {
  '1'=>{ 'agenda' => 
          [ {'YEAR'=>'2008','MONTH'=>'MARCH',   'COLOR_CODE'=>'1' },
            {'YEAR'=>'2014','MONTH'=>'APRIL',   'COLOR_CODE'=>'2' },
            {'YEAR'=>'2014','MONTH'=>'DECEMBER','COLOR_CODE'=>'3'},
          ], 
       },
  '2'=>{ 'agenda' => 
          [ {'YEAR'=>'2001','MONTH'=>'MAY', 'COLOR_CODE'=>'1' },
            {'YEAR'=>'2009','MONTH'=>'JUNE','COLOR_CODE'=>'2' },
            {'YEAR'=>'2001','MONTH'=>'MAY', 'COLOR_CODE'=>'1' },
            {'YEAR'=>'2009','MONTH'=>'JUNE','COLOR_CODE'=>'2' },
            {'YEAR'=>'2013','MONTH'=>'JULY','COLOR_CODE'=>'2' },
            {'YEAR'=>'2016','MONTH'=>'SEPTEMBER', 'COLOR_CODE'=>'4' } 
          ],
        },
};

my $recs = collect();
print Dumper $recs;

sub collect {

  my @all = ();
  foreach my $number ( keys %{$more_rec} ) {
    my $ar = $more_rec->{$number};
    for my $mth (@{$ar->{'agenda'}}){
      push @all, $mth;
    }
  }
  return \@all;
}

    [download]
    poj
[reply]
[d/l]
      Got it to work this way: 
      ...
push @all, @{$numbers->{agenda}};
...

      [download]
      Thank you!
[reply]
[d/l]

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