Thanks a lot for your help ! moritz

Concerning your remark to overcome the problem, could this work ? Thanks

 while (<$file>){
      chomp;
      my @items = split m/;/, $_;
      if (defined($items[1])){
         push @{$prices{$items[0]}, $items[1];
      }
      else{
      # add a ";" when there is a value void
          $prices{$items[0]} = "$prices{$items[0]}".";";   
   } 
}
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