Reference

Core Classes

Reference pages for Ruby core classes and constructors.

1. BasicObject#method_missing

   Intercept calls to undefined methods. method_missing is called when an object responds to no method by that name — use it to implement dynamic delegation, fl...

   method_missing(method_name, *args, &block)
2. Binding

   An object that encapsulates the execution context, including local variables, self, and method scope.

   Binding.new, binding()
3. Float

   A numeric class representing IEEE 754 double-precision floating-point numbers.

   Float.new, Float()
4. Integer

   The core class for whole numbers, including Fixnum (smaller) and Bignum (larger) in older Ruby.

   Integer()
5. Kernel#block_given?

   Returns true if a block was passed to the current method, otherwise returns false.

   block_given? -> true or false
6. Object#clone

   Create a shallow copy of an object. clone copies both instance variables and singleton class.

   obj.clone -> obj
7. Object#dup

   Create a shallow copy of an object. dup copies instance variables but not singleton methods.

   obj.dup -> obj
8. Object#frozen?

   Returns true if the object is frozen (immutable), false otherwise. Frozen objects cannot be modified.

   obj.frozen? -> true or false
9. Object#instance_of?

   Returns true if the object is an instance of exactly the given class, not its superclasses.

   obj.instance_of?(klass) -> true or false
10. Object#is_a?

    Checks whether an object is an instance of a given class or any of its superclasses. Returns true or false.

    obj.is_a?(klass) -> true or false
11. Object#kind_of?

    Returns true if the object is an instance of the given class or any of its superclasses.

    obj.kind_of?(klass) -> true or false
12. Object#nil?

    The nil? method returns true if an object is nil, false otherwise. It's the standard way to check for nil values in Ruby.

    obj.nil? -> true or false
13. Object#object_id

    Returns a unique integer identifier for a Ruby object. This integer is the object's memory address in the MRI implementation.

    obj.object_id -> integer
14. Object#respond_to?

    Checks whether an object responds to a given method, returning true or false. Essential for duck typing and dynamic method handling in Ruby.

    obj.respond_to?(method_name, include_all=false) -> true or false
15. Object#send

    Invokes the named method on the object, passing any arguments. send is the foundation for dynamic method calls in Ruby.

    obj.send(symbol, *args) -> obj
16. Object#tap

    Yields the object to a block and returns the object itself, useful for debugging or method chaining.

    obj.tap { |x| block } -> obj
17. Object#try

    Safely call a method on an object if it responds to it, returns nil otherwise

18. String#chomp!

    Removes trailing record separators from a string in-place. Modifies the original string.

    string.chomp! -> self or nil string.chomp!(separator) -> self or nil