Ruby: List Object Methods

In Ruby, practically everything is a “Object” in the sense of Object Oriented programing (OOP). Even numbers and strings are objects. What this effective means is that for any “thing” in Ruby, you can append it with .name where the name is a method (function).

e.g. 3 is a thing in Ruby. So, it has many methods, for example: to_i (convert to integer), to_s (convert to string), and you can call it like this: 3.to_i.

To find the methods of a thing, use the method methods. Example:

String object methods

# ruby

# methods for a string object
p "rabbit".methods ==
[:unicode_normalized?, :encode!, :unicode_normalize, :ascii_only?,
:unicode_normalize!, :to_r, :to_c, :encode, :include?, :%, :*, :+,
:unpack, :unpack1, :count, :partition, :+@, :-@, :<=>, :<<, :sum, :==,
:===, :next, :=~, :[], :[]=, :empty?, :casecmp, :eql?, :insert, :casecmp?,
:match?, :bytesize, :match, :next!, :succ!, :index, :upto, :replace,
:rindex, :chr, :clear, :byteslice, :getbyte, :setbyte, :freeze, :scrub,
:scrub!, :dump, :inspect, :intern, :upcase, :downcase, :capitalize,
:swapcase, :upcase!, :undump, :length, :size, :downcase!, :succ, :swapcase!,
:hex, :capitalize!, :split, :chars, :oct, :grapheme_clusters, :concat,
:codepoints, :lines, :bytes, :to_str, :end_with?, :start_with?, :reverse,
:reverse!, :sub, :to_s, :to_i, :to_f, :rjust, :center, :prepend, :crypt,
:ord, :chomp, :strip, :to_sym, :ljust, :delete_prefix, :delete_suffix,
:lstrip, :gsub, :scan, :chomp!, :sub!, :gsub!, :rstrip, :delete_prefix!,
:chop, :lstrip!, :rstrip!, :chop!, :delete_suffix!, :strip!, :tr_s,
:delete, :squeeze, :tr!, :tr, :delete!, :squeeze!, :each_line, :each_byte,
:tr_s!, :each_codepoint, :each_grapheme_cluster, :slice, :slice!, :each_char,
:encoding, :force_encoding, :b, :valid_encoding?, :rpartition, :hash,
:between?, :clamp, :<=, :>=, :<, :>, :singleton_class, :dup, :itself,
:taint, :tainted?, :untaint, :untrust, :untrusted?, :trust, :methods,
:singleton_methods, :protected_methods, :private_methods, :public_methods,
:instance_variables, :instance_variable_get, :instance_variable_set,
:instance_variable_defined?, :remove_instance_variable, :instance_of?,
:kind_of?, :is_a?, :display, :class, :frozen?, :tap, :then, :yield_self,
:public_send, :extend, :clone, :method, :public_method, :singleton_method,
:define_singleton_method, :!~, :nil?, :respond_to?, :object_id, :send,
:to_enum, :enum_for, :__send__, :!, :instance_eval, :instance_exec,
:!=, :equal?, :__id__]

Integer object methods

# ruby

# methods for a integer object
p 5.methods ==
[:anybits?, :nobits?, :downto, :times, :pred, :pow, :**, :<=>, :<<,
:>>, :<=, :>=, :==, :===, :next, :-@, :digits, :[], :odd?, :bit_length,
:even?, :upto, :%, :chr, :&, :*, :+, :inspect, :-, :/, :size, :succ,
:<, :>, :ord, :to_int, :to_s, :to_i, :to_f, :to_r, :integer?, :numerator,
:denominator, :rationalize, :gcd, :div, :divmod, :fdiv, :^, :gcdlcm,
:lcm, :coerce, :modulo, :remainder, :abs, :magnitude, :zero?, :floor,
:ceil, :round, :truncate, :|, :~, :allbits?, :dup, :+@, :infinite?,
:finite?, :eql?, :singleton_method_added, :quo, :real?, :arg, :rectangular,
:rect, :polar, :real, :imaginary, :imag, :abs2, :angle, :phase, :conj,
:to_c, :conjugate, :clone, :i, :nonzero?, :step, :positive?, :negative?,
:between?, :clamp, :singleton_class, :itself, :taint, :tainted?, :untaint,
:untrust, :untrusted?, :trust, :methods, :singleton_methods, :protected_methods,
:private_methods, :public_methods, :instance_variables, :instance_variable_get,
:instance_variable_set, :instance_variable_defined?, :remove_instance_variable,
:instance_of?, :kind_of?, :is_a?, :display, :hash, :class, :frozen?,
:tap, :then, :yield_self, :public_send, :extend, :method, :public_method,
:singleton_method, :define_singleton_method, :=~, :!~, :nil?, :respond_to?,
:freeze, :object_id, :send, :to_enum, :enum_for, :__send__, :!, :instance_eval,
:instance_exec, :!=, :equal?, :__id__]

Array object methods

# ruby

xx = [3,4,5]

# methods for a array object
p xx.methods ==
[:to_h, :include?, :&, :pack, :*, :+, :-, :shuffle!, :shuffle, :sample,
:at, :fetch, :last, :union, :difference, :intersection, :intersect?,
:push, :append, :pop, :shift, :unshift, :each_index, :join, :rotate,
:rotate!, :sort!, :sort_by!, :collect!, :map!, :select!, :filter!,
:keep_if, :values_at, :delete_at, :delete_if, :reject!, :transpose,
:fill, :sort, :assoc, :rassoc, :compact!, :flatten, :uniq!, :find_index,
:count, :select, :filter, :combination, :reject, :collect, :map, :repeated_permutation,
:flatten!, :permutation, :bsearch, :bsearch_index, :repeated_combination,
:product, :first, :all?, :any?, :one?, :none?, :minmax, :deconstruct,
:reverse_each, :zip, :|, :take, :take_while, :drop, :cycle, :drop_while,
:<=>, :<<, :uniq, :compact, :==, :sum, :[], :[]=, :empty?, :eql?, :insert,
:index, :rindex, :replace, :clear, :max, :min, :inspect, :length, :size,
:each, :reverse, :concat, :reverse!, :to_ary, :prepend, :to_a, :to_s,
:delete, :slice, :slice!, :dig, :hash, :chunk, :slice_before, :slice_after,
:slice_when, :chunk_while, :find, :chain, :lazy, :entries, :sort_by,
:grep, :grep_v, :detect, :find_all, :filter_map, :flat_map, :collect_concat,
:inject, :reduce, :partition, :group_by, :tally, :min_by, :max_by,
:minmax_by, :member?, :each_with_index, :each_entry, :each_slice, :each_cons,
:each_with_object, :singleton_class, :dup, :itself, :taint, :tainted?,
:untaint, :untrust, :untrusted?, :trust, :methods, :singleton_methods,
:protected_methods, :private_methods, :public_methods, :instance_variables,
:instance_variable_get, :instance_variable_set, :instance_variable_defined?,
:remove_instance_variable, :instance_of?, :kind_of?, :is_a?, :display,
:class, :frozen?, :tap, :then, :yield_self, :public_send, :extend,
:clone, :method, :public_method, :singleton_method, :define_singleton_method,
:===, :=~, :!~, :nil?, :respond_to?, :freeze, :object_id, :send, :to_enum,
:enum_for, :__send__, :!, :instance_eval, :instance_exec, :!=, :equal?,
:__id__]

List Class Methods

xx = Class.new

p xx.methods

# [:allocate, :superclass, :subclasses, :new, :public_instance_method,
# :define_method, :<=>, :<=, :>=, :==, :===, :included_modules, :include?,
# :ancestors, :attr, :attr_reader, :attr_writer, :attr_accessor, :instance_methods,
# :public_instance_methods, :protected_instance_methods, :private_instance_methods,
# :constants, :freeze, :inspect, :const_set, :const_get, :const_source_location,
# :const_defined?, :class_variable_set, :class_variables, :remove_class_variable,
# :class_variable_get, :const_missing, :class_variable_defined?, :<,
# :private_constant, :>, :singleton_class?, :public_constant, :deprecate_constant,
# :prepend, :include, :module_exec, :to_s, :module_eval, :class_exec,
# :class_eval, :remove_method, :undef_method, :alias_method, :method_defined?,
# :public_method_defined?, :private_method_defined?, :name, :protected_method_defined?,
# :public_class_method, :private_class_method, :autoload?, :autoload,
# :instance_method, :singleton_class, :dup, :itself, :taint, :tainted?,
# :untaint, :untrust, :untrusted?, :trust, :methods, :singleton_methods,
# :protected_methods, :private_methods, :public_methods, :instance_variables,
# :instance_variable_get, :instance_variable_set, :instance_variable_defined?,
# :remove_instance_variable, :instance_of?, :kind_of?, :is_a?, :display,
# :hash, :class, :frozen?, :tap, :then, :yield_self, :public_send, :extend,
# :clone, :method, :public_method, :singleton_method, :define_singleton_method,
# :=~, :!~, :nil?, :eql?, :respond_to?, :object_id, :send, :to_enum,
# :enum_for, :__send__, :!, :instance_eval, :instance_exec, :!=, :equal?,
# :__id__]