0b1

0b1 is a binary literal formed by the prefix 0b followed by binary digits. In base-2 notation, the digits after the prefix are read as bits, so 0b1 represents the decimal value 1. Other common binary literals include 0b10 (2) and 0b1010 (10).

In programming, the 0b prefix is used to express integer constants directly in base 2. This makes it convenient to specify bit patterns, masks, and flags without converting from decimal. The exact rules—such as which digits are allowed after 0b and whether readability separators are permitted—depend on the language.

Common language support includes Python, JavaScript (ES6), Java (since Java 7), C++ (since C++14), and Rust, all of which allow 0b-prefixed binary literals. Some languages also permit underscores for readability (for example, 0b1010_0011). Note that not all languages support binary literals, and some older contexts may treat numeric literals with leading zeros as octal values or apply other rules.

Summary: 0b1 denotes the binary value 1. The 0b prefix signals a base-2 literal in many modern programming languages, with usage and syntax varying by language but sharing the underlying concept of representing numbers as binary digits. See also hexadecimal literals (0x) and general binary notation in computer science.