%hash;
@array = (1212, 1216, 2112, 2111, 33154, 34458, 36339, 154, 556);               #Klassifizierung der Elemente nach der Anzahl der Zahlen
#$laenge_string = length $_;

for (@array)
{
        $laenge_string = length $_;     
#       print "$laenge_string\n";
        $anz = "mit".$laenge_string;
        unless($laenge_string eq $anderelaenge)
        {               
#               print "$_\n";
                push (@{$hash{$anz}}, $_);
        }
        else
        {
                $anderelaenge = $laenge_string;
        }       
}

%hash;
@array = (1212, 1216, 2112, 2111, 33154, 34458, 36339, 154, 556);

for my $nr ( @array ){
    push @{ $hash{length $nr} }, $nr;
}

for my $length ( sort keys %hash ){
    print join(" ", @{ $hash{$length} }),"\n";
}