Quality facets - barcodes that have a strange number of digits, or a bad last digit key

[stephanegigandet]

What

From @cquest:

length | count
--------+--------
0 | 1
1 | 10
2 | 77
3 | 183
4 | 269
5 | 385
6 | 468
7 | 381
8 | 49154
9 | 210
10 | 530
11 | 2855
12 | 1643
13 | 808324
14 | 696
15 | 290
16 | 50
17 | 12
18 | 36
19 | 5
20 | 47
21 | 7
22 | 26
23 | 2
24 | 70
25 | 3
26 | 35
27 | 4
28 | 5
29 | 1
30 | 5
31 | 5
32 | 13
33 | 1
34 | 7
35 | 4
36 | 2
37 | 4
38 | 4
39 | 2
40 | 6
41 | 2
42 | 3
43 | 2
44 | 2
45 | 4
46 | 2
48 | 3
49 | 2
65 | 1
69 | 1
| 130

Part of

• 🧽 Data quality (tracker) #5538

[bredowmax]

Have you already tested how many barcodes have a correct check digit? I've found quite a few type-o's where I assume the check digit must be incorrect. For example the first digit of the barcode of this product https://world.openfoodfacts.org/product/5337226537658/nougat-pockets-k-classic

More:
https://en.wikipedia.org/wiki/Check_digit

[bredowmax]

Some of the 6, 7 or 11-digit barcodes might be due to a leading 0 that was removed when processing these numbers

[bredowmax]

The barcodes that are longer than 13 digits might be Code 128 or GS1-128 codes, which is not necessarily wrong input but just a longer barcode that is sometimes used for fresh products that vary in weight or price

https://en.wikipedia.org/wiki/Code_128
https://en.wikipedia.org/wiki/GS1-128

See also openfoodfacts/openfoodfacts-ios#563