my %hash1 = (key1 => 'value1',
                key2 => 'value2');
my %hash1 = (key3 => 'value3',
                key4 => 'value4');
my %hash_gesamt = (%hash1,%hash2);
#oder
%hash1 = (%hash1,%hash2);

my @array = (1..4);
my @array2 = (5..11);
#entweder
my @array3 = (@array,@array2);
#oder
push(@array,@array2);

my $size = (@a1>@a2?@a2:@a1);

#! /usr/bin/perl

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

my @array = ({key1 => 'value1',
               key2 => 'value2'});
my @array2 = ({key3 => 'value3',
               key4 => 'value4'},
              {key5 => 'value5'});

my @new_array = @{join_arrays(\@array,\@array2)};

print Dumper(\@new_array);

sub join_arrays{
  my ($ar1ref,$ar2ref) = @_;
  my @array = ();
  if(scalar(@{$ar2ref}) > scalar(@{$ar1ref})){
    my $tempref = $ar2ref;
    $ar2ref = $ar1ref;
    $ar1ref = $tempref;
  }
  for(0..(scalar(@{$ar1ref}) - 1)){
    $array[$_] = ${$ar1ref}[$_];
    %{$array[$_]} = (%{$array[$_]},%{${$ar2ref}[$_]}) if(${$ar2ref}[$_]);
  }
  return \@array;
}

my @keys = keys %hash;
@hash2{@keys}=@hash1{@keys}