# Alphanumeric Identifier

Key: `representation.identifier.alphanumeric_id`

Mixed letter-and-digit identifier string that doesn't match a known specific format. Examples: product codes ("SKU-12345"), cabin numbers ("C85"), ticket IDs ("A/5 21171"), lot numbers ("LOT-2024-0042"), license plates ("ABC 1234"). Format-detectable: contains both alphabetic and numeric characters.

Page: <https://meridian.online/docs/projects/finetype/types/representation/identifier/alphanumeric_id>

Samples: `SKU-12345`, `C85`, `A/5 21171`, `LOT-2024-0042`, `ABC 1234`, `REF-00742`, `B28`, `FL-2087`

## Background

### Origin

FineType defines the Alphanumeric Identifier type itself, to catch mixed letter-and-digit identifiers that fall through more specific types such as UUID, ISIN and IATA codes.[[1]](https://github.com/meridian-online/finetype/blob/main/labels/definitions_representation.yaml) FineType's validation pattern for the type requires at least one letter and at least one digit.[[1]](https://github.com/meridian-online/finetype/blob/main/labels/definitions_representation.yaml)

### Use

Microsoft Excel, with default settings, is known to convert gene names to dates and floating-point numbers.[[2]](https://pmc.ncbi.nlm.nih.gov/articles/PMC4994289/) A programmatic scan of leading genomics journals found that approximately one-fifth of papers with supplementary Excel gene lists contained erroneous gene name conversions.[[2]](https://pmc.ncbi.nlm.nih.gov/articles/PMC4994289/) Microsoft's support documentation says Excel automatically removes leading zeros and converts large numbers to scientific notation.[[3]](https://support.microsoft.com/en-us/office/keeping-leading-zeros-and-large-numbers-1bf7b935-36e1-4985-842f-5dfa51f85fe7)

The ELF code in GLEIF's ISO 20275 Entity Legal Forms code list is an alpha-numeric code of four characters from the basic Latin character set.[[4]](https://www.gleif.org/en/about-lei/code-lists/iso-20275-entity-legal-forms-code-list) Before settling on a generic label for a column of short mixed codes, check whether the codes belong to a published scheme such as the ELF list, since a published list can be validated value by value. (Meridian's view)

### Where you'll meet it

In a published copy of the Titanic passenger dataset, the Ticket column mixes values such as A/5 21171 and PC 17599 with plain numbers such as 113803.[[5]](https://raw.githubusercontent.com/datasciencedojo/datasets/master/titanic.csv) The Titanic passenger file's Cabin column holds codes such as C85 and C123.[[5]](https://raw.githubusercontent.com/datasciencedojo/datasets/master/titanic.csv) A ticket column like the Titanic one shows that a single field can hold several identifier shapes at once, so a profile of mixed codes is worth reading row by row before you trust it. (Meridian's view)

## Sources

1. [finetype/labels/definitions\_representation.yaml at main · meridian-online/finetype · GitHub](https://github.com/meridian-online/finetype/blob/main/labels/definitions_representation.yaml) — FineType
2. [Gene name errors are widespread in the scientific literature](https://pmc.ncbi.nlm.nih.gov/articles/PMC4994289/) — secondary source
3. [Keeping leading zeros and large numbers](https://support.microsoft.com/en-us/office/keeping-leading-zeros-and-large-numbers-1bf7b935-36e1-4985-842f-5dfa51f85fe7) — documentation
4. [ISO 20275: Entity Legal Forms Code List - Code Lists - LEI Data – GLEIF](https://www.gleif.org/en/about-lei/code-lists/iso-20275-entity-legal-forms-code-list) — organisation
5. [titanic.csv](https://raw.githubusercontent.com/datasciencedojo/datasets/master/titanic.csv) — dataset