hexprefixed

Hexprefixed is a term used to describe numeric literals or data values that begin with a prefix indicating hexadecimal (base-16) notation. In programming and data formats, a hexprefixed value is intended to be interpreted as a hexadecimal number rather than a decimal one.

The most common prefix is 0x or 0X, used in languages such as C, C++, Java, JavaScript, Rust, and Go. The 0x prefix originates from the C language and has become a de facto standard in many ecosystems for representing hex literals. In blockchain and web data, especially Ethereum and many JSON-based protocols, hexprefixed strings often appear with 0x to denote hex-encoded data or addresses.

After the prefix, the character set includes digits 0–9 and letters A–F (case-insensitive). Some languages allow underscores or separators for readability, and many languages accept both lowercase and uppercase hex digits. In most languages, the prefix is part of the token but not part of the numerical value; parsing treats the substring after 0x as a hex number. Some languages distinguish between numeric literals and strings, requiring quotes for the latter.

Examples: 0x1A3F represents the decimal value 6719; 0xFF00 is 65280; 0xdeadBeef is a common mnemonic hex literal. Colors in code may use hex values, while color literals in CSS use a different format (#RRGGBB).

Variations exist; some languages use different prefixes or suffixes for hex. The term hexprefixed is sometimes hyphenated as hex-prefixed in documentation to describe a convention rather than a language feature. Good practice is to be consistent with the language’s style guide and to clearly distinguish between numeric literals and string data.