Objects in Ruby

In Ruby, all numbers, strings, arrays, regular expressions, and many other entities are actually objects. Work is done by executing the methods belonging to the object:

3.succ                 # 4
"abc".upcase           # "ABC"
[2,1,5,3,4].sort       # [1,2,3,4,5]
someObject.someMethod  # some result

In Ruby, every object is an instance of some class; the class contains the implementation of the methods:

"abc".class        # String
"abc".class.class  # Class

In addition to encapsulating its own attributes and operations, an object in Ruby has an identity:

"abc".object_id   # 53744407

This object ID is usually of limited usefulness to the programmer.