# use liz's technique
  foreach my $i ( reverse 0 .. $#AoH_all )
  {
      if ( $exclude{ $AoH_all[$i]{id} } )
      {
          splice @AoH_all, $i, 1;
      }
  }

  # keep track of things manually
  my $n_elt = @AoH_all;
  for ( my $i = 0; $i < $n_elt; ++$i )
  {
      if ( $exclude{ $AoH_all[$i]{id} } )
      {
          splice @AoH_all, $i, 1;
          --$n_elt;
          # whoops, bug here, see update...
      }
  }

  # finally, perl updates the length of @AoH_all for us, so:
  for ( my $i = 0; $i < @AoH_all; ++$i )
  {
      if ( $exclude{ $AoH_all[$i]{id} } )
      {
          splice @AoH_all, $i, 1;
          # whoops, bug here, see update...
      }
  }