End of Life Ruby 3.1 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →

instance method

Object#is_a?

obj.is_a?(class) → true or false

VALUE
rb_obj_is_kind_of(VALUE obj, VALUE c)
{
    VALUE cl = CLASS_OF(obj);

    // Note: YJIT needs this function to never allocate and never raise when
    // `c` is a class or a module.
    c = class_or_module_required(c);
    return RBOOL(class_search_ancestor(cl, RCLASS_ORIGIN(c)));
}

Alias of #kind_of?

Returns true if class is the class of obj, or if class is one of the superclasses of obj or modules included in obj.

Example

module M;    end
class A
  include M
end
class B < A; end
class C < B; end

b = B.new
b.is_a? A          #=> true
b.is_a? B          #=> true
b.is_a? C          #=> false
b.is_a? M          #=> true

b.kind_of? A       #=> true
b.kind_of? B       #=> true
b.kind_of? C       #=> false
b.kind_of? M       #=> true

See also #kind_of? #instance_variable_set #itself #instance_variables also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.0

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