The Ruby Object Model

Question 1 of 10

1

What is the output from the last line:

class First; end
f = First.new
puts f.class.superclass

Select one of the following:

```
First
```
```
Object
```
```
nil
```
```
BasicObject
```

Explanation

Question 2 of 10

3

Complete the output from the following ruby statement:

> Class.ancestors
[ Class, ❌, ❌, ❌, BasicObject ]

Drag and drop to complete the text.

Module

EigenClass

Object

BasicModule

Kernel

Explanation

Question 3 of 10

1

What is the output from the following ruby code:

d = Developer.new
puts d.singleton_class.superclass

Select one of the following:

```
Object
```
```
BasicObject
```
```
Developer
```
```
Class
```

Explanation

Question 4 of 10

1

What is the output from final statement:

module A; end
module B; end
class Foo
  include A
  include B
end

puts Foo.new.class.ancestors[1]

Select one of the following:

```
Foo
```
```
A
```
```
B
```
```
Object
```

Explanation

Question 5 of 10

3

Select from the dropdown lists to complete the text.

Complete the last line of the following ruby console output:

>> class Bar; end
=> nil
>> Bar.ancestors
=> [Bar, Object, Kernel, BasicObject]
>> Bar.ancestors.map(&:class)
=> [Class, ( Class, Module ), ( Module, Class ), ( Class, Module )]

Explanation

Question 6 of 10

❌ ^-

2

Which of the following Object methods come from the BasicObject class

Select one or more of the following:

#object_id
#equal?
#inspect
#instance_of
#!=

Explanation

Question 7 of 10

1

What is the output from the last line

class Baz; end
baz = Baz.new

puts baz.singleton_class.ancestors.size

Select one of the following:

3
4
5

Explanation

Question 8 of 10

1

Select from the dropdown list to complete the text.

Complete the code below to achieve the desired output:

class Qux; end
Qux.( class_eval, instance_eval, new, tap ){ def toil; end }

>> Qux.instance_methods(false)
=> [:toil]

Explanation

Question 9 of 10

1

What is the output form the final puts statement

module Italian
  def speak
    "#{super} ?"
  end
end

module Boxer
  def speak
    "Grrr, #{super}"
  end
end

class Rocky
  prepend Italian
  include Boxer
  def speak
    "Yo Adrian"
  end
end

puts Rocky.new.speak

Select one of the following:

Yo Adrian ?
Grr, Yo Adrian ?
Grr, Yo Adrian
Grr, ?
Yo Adrian

Explanation

Question 10 of 10

❌ ^-

2

Given these definitions,

class User
  def breathe; end
end
u = User.new
def u.dance; end

Which of the following statements are truthful.

Select one or more of the following:

u.class.instance_methods(false).include?(:breathe)

u.class.instance_methods(false).include?(:dance)

u.singleton_class.instance_methods(false).include?(:dance)

u.singleton_class.instance_methods(false).include?(:breathe)

	Created by Domhnall Murphy almost 2 years ago

Think you know the Ruby Object Model. Have a go at this 10 question quiz to see how deep that knowledge goes.

The Ruby Object Model

The Ruby Object Model

Question 1 of 10

What is the output from the last line: class First; end f = First.new puts f.class.superclass

Select one of the following:

Explanation

Question 2 of 10

Complete the output from the following ruby statement: > Class.ancestors [ Class, ❌, ❌, ❌, BasicObject ]

Drag and drop to complete the text.

Explanation

Question 3 of 10

What is the output from the following ruby code: d = Developer.new puts d.singleton_class.superclass

Select one of the following:

Explanation

Question 4 of 10

What is the output from final statement: module A; end module B; end class Foo include A include B end puts Foo.new.class.ancestors[1]

Select one of the following:

Explanation

Question 5 of 10

Select from the dropdown lists to complete the text.

Complete the last line of the following ruby console output: >> class Bar; end => nil >> Bar.ancestors => [Bar, Object, Kernel, BasicObject] >> Bar.ancestors.map(&:class) => [Class, Class Module( Class, Module ), Module Class( Module, Class ), Class Module( Class, Module )]

Explanation

Question 6 of 10

Which of the following Object methods come from the BasicObject class

Select one or more of the following:

Explanation

Question 7 of 10

What is the output from the last line class Baz; end baz = Baz.new puts baz.singleton_class.ancestors.size

Select one of the following:

Explanation

Question 8 of 10

Select from the dropdown list to complete the text.

Complete the code below to achieve the desired output: class Qux; end Qux.class_eval instance_eval new tap( class_eval, instance_eval, new, tap ){ def toil; end } >> Qux.instance_methods(false) => [:toil]

Explanation

Question 9 of 10

What is the output form the final puts statement module Italian def speak "#{super} ?" end end module Boxer def speak "Grrr, #{super}" end end class Rocky prepend Italian include Boxer def speak "Yo Adrian" end end puts Rocky.new.speak

Select one of the following:

Explanation

Question 10 of 10

Given these definitions, class User def breathe; end end u = User.new def u.dance; end Which of the following statements are truthful.

Select one or more of the following:

Explanation

What is the output from the last line:
`class First; end f = First.new puts f.class.superclass`

Complete the output from the following ruby statement:
`> Class.ancestors [ Class, ❌, ❌, ❌, BasicObject ]`

What is the output from the following ruby code:
`d = Developer.new puts d.singleton_class.superclass`

What is the output from final statement:
`module A; end module B; end class Foo include A include B end puts Foo.new.class.ancestors[1]`

Complete the last line of the following ruby console output:
`>> class Bar; end => nil >> Bar.ancestors => [Bar, Object, Kernel, BasicObject] >> Bar.ancestors.map(&:class) => [Class, ( Class, Module ), ( Module, Class ), ( Class, Module )]`

What is the output from the last line
`class Baz; end baz = Baz.new puts baz.singleton_class.ancestors.size`

Complete the code below to achieve the desired output:
`class Qux; end Qux.( class_eval, instance_eval, new, tap ){ def toil; end } >> Qux.instance_methods(false) => [:toil]`

What is the output form the final puts statement
`module Italian def speak "#{super} ?" end end module Boxer def speak "Grrr, #{super}" end end class Rocky prepend Italian include Boxer def speak "Yo Adrian" end end puts Rocky.new.speak`

Given these definitions,
`class User def breathe; end end u = User.new def u.dance; end`

Which of the following statements are truthful.