alfanumerisk

Alfanumerisk is a term used to describe strings or character sets that combine letters and digits. In English, this is known as alphanumeric. In strict terms, an alphanumeric string contains only letters and numbers (for example, A–Z, a–z, and 0–9), with no punctuation or symbols. In practice, many systems treat the concept more broadly and may allow additional Unicode letters or certain separators, depending on the context.

Common uses include data validation, identifiers, usernames, passwords, product codes, and license keys. Alphanumeric input helps distinguish values and expands the pool of possible combinations, which can improve security for passwords or reduce ambiguity in codes while remaining human-readable.

Distinctions are often made between alphanumeric, alphabetic, and numeric. Alphabetic strings consist solely of letters, numeric strings consist solely of digits, and alphanumeric strings mix both. Some definitions require at least one letter and one digit to be considered alphanumeric; others simply refer to strings drawn from the combined set of letters and digits. Locale and encoding considerations matter: ASCII defines a basic set of letters and digits, while Unicode allows letters from many scripts, which influences what counts as alphanumeric in different applications.

Examples of alphanumeric strings include "ABC123", "user42", and "u8r9z". Non-examples include "123456" (numeric) and "abcdef" (alphabetic). Understanding the intended definition is important for validation rules and database constraints.