檢視物件方法

檢查物件

你可以使用 methods 或 public_methods 方法找到物件可以響應的公共方法，該方法返回符號陣列：

class Foo
  def bar; 42; end
end
f = Foo.new
def f.yay; 17; end
p f.methods.sort
#=> [:!, :!=, :!~, :<=>, :==, :===, :=~, :__id__, :__send__, :bar, :class, :clone,
#=>  :define_singleton_method, :display, :dup, :enum_for, :eql?, :equal?, :extend,
#=>  :freeze, :frozen?, :hash, :inspect, :instance_eval, :instance_exec,
#=>  :instance_of?, :instance_variable_defined?, :instance_variable_get,
#=>  :instance_variable_set, :instance_variables, :is_a?, :itself, :kind_of?, 
#=>  :method, :methods, :nil?, :object_id, :private_methods, :protected_methods,
#=>  :public_method, :public_methods, :public_send, :remove_instance_variable,
#=>  :respond_to?, :send, :singleton_class, :singleton_method, :singleton_methods,
#=>  :taint, :tainted?, :tap, :to_enum, :to_s, :trust, :untaint, :untrust,
#=>  :untrusted?, :yay]

對於更有針對性的列表，你可以刪除所有物件共有的方法，例如

p (f.methods - Object.methods).sort
#=> [:bar,:yay]

或者，你可以將 false 傳遞給 methods 或 public_methods：

p f.methods(false) # public and protected singleton methods of `f`
#=> [:yay]

p f.public_methods(false)
#=> [:yay, :bar]

你可以使用 private_methods 和 protected_methods 找到物件的私有和受保護方法：

p f.private_methods.sort
#=> [:Array, :Complex, :DelegateClass, :Float, :Hash, :Integer, :Rational, :String,
#=>  :__callee__, :__dir__, :__method__, :`, :abort, :at_exit, :autoload, :autoload?,
#=>  :binding, :block_given?, :caller, :caller_locations, :catch,
#=>  :default_src_encoding, :eval, :exec, :exit, :exit!, :fail, :fork, :format, :gem,
#=>  :gem_original_require, :gets, :global_variables, :initialize, :initialize_clone,
#=>  :initialize_copy, :initialize_dup, :irb_binding, :iterator?, :lambda, :load,
#=>  :local_variables, :loop, :method_missing, :open, :p, :print, :printf, :proc,
#=>  :putc, :puts, :raise, :rand, :readline, :readlines, :require, :require_relative,
#=>  :respond_to_missing?, :select, :set_trace_func, :singleton_method_added,
#=>  :singleton_method_removed, :singleton_method_undefined, :sleep, :spawn,
#=>  :sprintf, :srand, :syscall, :system, :test, :throw, :trace_var, :trap,
#=>  :untrace_var, :warn]

p f.protected_methods
#=> []

與 methods 和 public_methods 一樣，你可以將 false 傳遞給 private_methods 和 protected_methods 以修剪掉繼承的方法。

檢查類或模組

除了 methods，public_methods，protected_methods 和 private_methods 之外，類和模組還公開了 instance_methods，public_instance_methods，protected_instance_methods 和 private_instance_methods，以確定為從類或模組繼承的物件公開的方法。如上所述，你可以將 false 傳遞給這些方法以排除繼承的方法：

p Foo.instance_methods.sort
#=> [:!, :!=, :!~, :<=>, :==, :===, :=~, :__id__, :__send__, :bar, :class,
#=>  :clone, :define_singleton_method, :display, :dup, :enum_for, :eql?,
#=>  :equal?, :extend, :freeze, :frozen?, :hash, :inspect, :instance_eval,
#=>  :instance_exec, :instance_of?, :instance_variable_defined?,
#=>  :instance_variable_get, :instance_variable_set, :instance_variables,
#=>  :is_a?, :itself, :kind_of?, :method, :methods, :nil?, :object_id,
#=>  :private_methods, :protected_methods, :public_method, :public_methods,
#=>  :public_send, :remove_instance_variable, :respond_to?, :send,
#=>  :singleton_class, :singleton_method, :singleton_methods, :taint,
#=>  :tainted?, :tap, :to_enum, :to_s, :trust, :untaint, :untrust, :untrusted?]

p Foo.instance_methods(false)
#=> [:bar]

最後，如果你將來忘記了其中大部分的名稱，你可以使用 methods 找到所有這些方法：

p f.methods.grep(/methods/)
#=> [:private_methods, :methods, :protected_methods, :public_methods,
#=>  :singleton_methods]

p Foo.methods.grep(/methods/)
#=> [:public_instance_methods, :instance_methods, :private_instance_methods,
#=>  :protected_instance_methods, :private_methods, :methods,
#=>  :protected_methods, :public_methods, :singleton_methods]