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

Based on the 3 conditions I need to generate 3 arrays of hashes ( long data from DB) and join them into 1, maintaining the same format. The format I get from the DB is this: 
[
{fruit=>apple,
vegetable=> pumpkin,
},
{fruit=>mango,
vegetable=> tomatoes,
},
{fruit=>strawberry,
vegetable=> pumpkin,
},

]

[download]
So all potential hashes will be generated in this format. I tried the following: 
my $arrayHash1 =();
my $arrayHash2 =();
my $arrayHash3 =();
my $FinalMegaHash =();

if ( condition1==true){
generate arrayHash1;
$FinalMegaHash .= $arrayHash1;
}
if ( condition2==true){
generate arrayHash2;
$FinalMegaHash .= $arrayHash2;
}
if ( condition3==true){
generate arrayHash3;
$FinalMegaHash .= $arrayHash3;
}
print Dumper $FinalMegaHash;

[download]
I know the syntax is wrong, but it illustrates the idea of what I want to do. Have been googling all over the place, can't find anything. :/ Any guidance would be much appreciated. Thank you

Replies are listed 'Best First'.
Re: combining 3 arrays of hashes
by johngg (Canon) on Aug 19, 2016 at 19:57 UTC

    Firstly, use the @ sigil for arrays. Secondly, string concatenation is not appropriate for arrays, use push instead. Here is a simplified solution.

    johngg@shiraz:~/perl/Monks > perl -MData::Dumper -Mstrict -Mwarnings -
+E '
my @AoH1 = (
   { fruit => q{apple}, veg => q{pumpkin} },
   { fruit => q{pear}, veg => q{swede} },
   { fruit => q{cherry}, veg => q{pea} }
   );
my @AoH2 = (
   { fruit => q{mango}, veg => q{cabbage} },
   { fruit => q{plum}, veg => q{leek} },
   );
my @megaAoH = ();
push @megaAoH, @AoH1 if 1;
push @megaAoH, @AoH2 if 1;
print Data::Dumper->Dumpxs( [ \ @megaAoH ], [ qw{ *megaAoH } ] );'
@megaAoH = (
             {
               'fruit' => 'apple',
               'veg' => 'pumpkin'
             },
             {
               'veg' => 'swede',
               'fruit' => 'pear'
             },
             {
               'fruit' => 'cherry',
               'veg' => 'pea'
             },
             {
               'veg' => 'cabbage',
               'fruit' => 'mango'
             },
             {
               'fruit' => 'plum',
               'veg' => 'leek'
             }
           );
johngg@shiraz:~/perl/Monks >

    [download]

    I hope this is helpful.

    Update: If you are actually using array references rather than arrays then square brackets should be used instead of parentheses and de-reference them for the push operation.

    johngg@shiraz:~/perl/Monks > perl -MData::Dumper -Mstrict -Mwarnings -
+E '
my $refToAoH1 = [
   { fruit => q{apple}, veg => q{pumpkin} },
   { fruit => q{pear}, veg => q{swede} },
   { fruit => q{cherry}, veg => q{pea} }
   ];
my $refToAoH2 = [
   { fruit => q{mango}, veg => q{cabbage} },
   { fruit => q{plum}, veg => q{leek} },
   ];
my $refTomegaAoH = [];
push @{ $refTomegaAoH }, @{ $refToAoH1 } if 1;
push @{ $refTomegaAoH }, @{ $refToAoH2 } if 1;
print Data::Dumper->Dumpxs( [ $refTomegaAoH ], [ qw{ refTomegaAoH } ] 
+);'
$refTomegaAoH = [
                  {
                    'fruit' => 'apple',
                    'veg' => 'pumpkin'
                  },
                  {
                    'fruit' => 'pear',
                    'veg' => 'swede'
                  },
                  {
                    'fruit' => 'cherry',
                    'veg' => 'pea'
                  },
                  {
                    'fruit' => 'mango',
                    'veg' => 'cabbage'
                  },
                  {
                    'veg' => 'leek',
                    'fruit' => 'plum'
                  }
                ];
johngg@shiraz:~/perl/Monks >

    [download]

    Cheers,

    JohnGG

[reply]
[d/l]
[select]
      JohnGG - You are the best! The second solution for the array references worked like a charm. Thank you SO much! Have a wonderful weekend
[reply]

Back to Seekers of Perl Wisdom