10xxxx

10xxxx is not a formal term with a single, universal definition. In practice it functions as a placeholder string used in documentation, tutorials, and sample data to illustrate a six-character code with a fixed prefix and a variable suffix. The first two characters, 10, are shown as constant, while the trailing four characters represented by xxxx are placeholders that may be substituted with digits, letters, or a mix, depending on the system or dataset.

In pattern matching and programming contexts, 10xxxx is often described as a six-character string starting with 10 followed by four wildcard positions. A simple regular expression to match such strings is ^10.{4}$, where the dot represents any character and {4} specifies four repetitions. Variants may restrict the allowed character set, for example ^10[0-9A-Za-z]{4}$, depending on domain rules and data integrity requirements.

Usage examples include mock product keys, serial numbers, or file identifiers used in manuals and training materials. Because 10xxxx is a placeholder rather than a defined standard, its exact meaning and allowed characters are determined by the specific context or documentation in which it appears. Real-world implementations replace the xxxx portion with values defined by organizational conventions or software systems, rather than implying a universal standard.

See also: placeholder, wildcard, pattern, regular expression, mock data.