[ next ] [ prev ] [ contents ]

XP-Cinti TDD Workshop

Ruby Symbols

An identifier preceeded by a colon (e.g. :BLACK) is a Symbol object. Symbols are much like strings, but with the following properties.

For each symbol literal (e.g. :BLACK) there is one and only one symbol object that represents it. This guarantees that no matter where in the program you reference the symbol :BLACK, it will always be the same symbol object.
Comparing symbols is faster than comparing strings. Symbol comparison only checks to see if the reference is the same. String comparisons need to compare the entire string.

Symbols are used internally by Ruby to implement method names. Ruby programmers often use Symbols as named enumerations (e.g. :RED, :GREEN, :BLUE).

[ next ] [ prev ] [ contents ]