# Keep Leading Zeros in Product IDs When Cleaning Supplier CSVs

Authored ToolFlowKit practice material. These records are teaching examples, not customer data, current vendor offers, or measured software results.

## What should an identifier round-trip preserve?

These are authored examples, not an export produced by a tested application. If the zeros were already lost before you received the file, return to an authoritative supplier record. Padding every value to an assumed length could create convincing but incorrect IDs.

These comparison rows are authored fixtures. Compare strings before and after import, including leading zeros and variant suffixes. If the source already lacks the zeros, ask for the authoritative identifier rather than applying a padding rule. A successful numeric sum does not prove that the identifiers survived.

| Source value | Proposed change | Review decision |
| --- | --- | --- |
| 00127 | 127 | Reject: original characters were removed. |
| AB-07 | AB07 | Confirm a supplier matching rule before removing the hyphen. |
| sku-a | SKU-A | Keep the original; any case-normalized key belongs in a separate field. |

## Check the completed record



| Source string | Exported string | Decision |
| --- | --- | --- |
| 00127 | 00127 | Keep as text |
| 00127 | 127 | Reject the import/export route; zeros lost |
| 127 | 00127 guessed from length | Do not infer the supplier's intended ID |

Guide: https://toolflowkit.com/guides/preserve-product-identifiers

License: CC0 1.0.