while ( <> ) {
    my ( $part_num, undef, $designator ) = split /,/, $_, 3 or next;
    push @{ $data{ $part_num } }, $designator =~ /[^",\s]+/g;
    }

for my $part_num ( sort keys %data ) {
    my $quantity = @{ $data{ $part_num } };
    print
        "$part_num,$quantity,",
        $quantity == 1 ? '' : '"',
        join( ',', sort {
            my ( $aL, $aR ) = $a =~ /(\D+)(\d+)/;
            my ( $bL, $bR ) = $b =~ /(\D+)(\d+)/;
            $aL cmp $bL || $aR <=> $bR
            } @{ $data{ $part_num } } ),
        $quantity == 1 ? '' : '"',
        "\n";
    }
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