Q1. Assume that the following code must have the stated execution result.
__(1)__
x.each_line { |line| puts line }
[Execution Result]
apple
banana
Which option can be inserted into __(1)__? (Choose one.)
A:
require "stringbuffer"
x = StringBuffer.new("apple\nbanana\n")
B:
require "stringio"
x = StringIO.new("apple\nbanana\n")
C:
require "strio"
x = StrIO.new("apple\nbanana\n")
D:
require "mockio"
x = MockIO.new("apple\nbanana\n")
Q2. Given the following code:
module I
end
module P
end
class C
include I
prepend P
end
p C.ancestors
Which option corresponds to the execution result? (Choose one.)
A: [P, C, I, Object, Kernel, BasicObject]
B: [C, P, I, Object, Kernel, BasicObject]
C: [C, I, Object, Kernel, BasicObject, P]
D: [P, I, C, Object, Kernel, BasicObject]
Q3. Assume that the following code must have the stated execution result:
x = __(1)__
p x + 1
[Execution Result]
(4/3)
Which option can be inserted into __(1)__? (Choose one.)
A: 1 / 3r
B: 1 / 3R
C: 1 / %r(3)
D: 1 / 3
Q4. Assume that the following code must have the stated execution result:
p ("aaaaaa".."zzzzzz").lazy.select { |e| e.end_with?("f") }.__(1)__
[Execution Result]
["aaaaaf", "aaaabf", "aaaacf"]
Which of the following options can be inserted into __(1)__? (Choose all that apply.)
A: first(3)
B: take(3)
C: take(3).force
D: first(3).force
Q5: Given the following code:
arr = []
f = Fiber.new {
arr << "A"
Fiber.yield "B"
Fiber.yield "C"
}
arr << "X"
arr << f.resume
arr << "Y"
p arr
Which option corresponds to the execution result? (Choose one.)
A: ["A", "B", "C", "X", "Y"]
B: ["X", "A", "B", "Y"]
C: ["X", "A", "B", "C", "Y"]
D: ["X", "A", nil, "Y"]
Q6. Assume that the following code must have the stated execution result:
class A
def foo
__1__
end
private
def bar
"baz"
end
end
p A.new.foo
[Execution Result]
"baz"
Which option can be inserted into __(1)__? (Choose one.)
A: bar
B: self.bar
C: A.new.bar
D: None of the above.
Q7. Assume that the following code must have the stated execution result.
class Greeter
class << self
def hello
puts "Hello there!"
end
end
end
__(1)__
[Execution Result]
Hello there!
Which of the following options can be inserted into __(1)__? (Choose two.)
A: Greeter.new.hello
B: Greeter.hello
C: Greeter.new.class.hello
D: Greeter.class.new.hello
Q8: Assume that the following code must have the stated execution result.
__(1)__
p multiply_by(4) { 2 + 3 }
[Execution Result]
20
Which of the following options can be inserted into __(1)__? (Choose two.)
A:
def multiply_by(n, &block)
n * block.call
end
B:
def multiply_by(n, &block)
n * block
end
C:
def multiply_by(n)
n * yield
end
D:
def multiply_by(n)
n * yield.call
end
Q9: Assume that the following code must have the stated execution result.
__(1)__
p sum { |e| e << 1 << 5 << 7 }
[Execution Result]
13
Which of the following options can be inserted into __(1)__? (Choose two.)
A:
def sum(&block)
array = []
block(array)
array.reduce(:+)
end
B:
def sum(&block)
array = []
block.call(array)
array.reduce(:+)
end
C:
def sum
array = []
yield(array)
array.reduce(:+)
end
D:
def sum
array = []
yield.call(array)
array.reduce(:+)
end
Q10. Given the following code:
class A
@@x = 1
end
class B < A
def self.x
@@x
end
end
class C < A
def self.inc
@@x += 1
end
end
C.inc
p B.x
Which option corresponds to the execution result? (Choose one.)
-
A:
1 -
B:
2 -
C:
3 -
D: An exception is raised
Q11. Assume that the following code must have the stated execution result:
words = ["apple", "banana", "cabbage"]
pop = Proc.new { words.pop }
3.times{ puts __(1)__ }
[Execution Result]
cabbage
banana
apple
Which option can be inserted into __(1)__? (Choose one.)
A: pop.load
B: pop.send
C: pop.run
D: pop.call
E: pop.eval
Q12. Assume that the following code must have the stated execution result:
words = ["apple", "banana", "cabbage"]
pop = __(1)__{ words.pop }
3.times{ puts pop.call }
[Execution Result]
cabbage
banana
apple
Which of the following options can be inserted into __(1)__? (Choose two.)
A: Proc.new
B: Block.new
C: lambda
D: Lambda.new
Q13. Assume that the following code must have the stated execution result.
add = __(1)__
puts add.call("hello")
[Execution Result]
HELLO
Which option can be inserted into __(1)__? (Choose one.)
A: ->(e) { e.upcase }
B: \(e) -> { e.upcase }
C: -> { (e) e.upcase }
D: -> { |e| e.upcase }
Q14. Assume that the following code must have the stated execution result:
old_data = [1,2,3]
old_data.freeze
new_data = old_data.__(1)__
new_data << 4
p new_data
[Execution Result]
[1,2,3,4]
Which option can be inserted into __(1)__? (Choose one.)
A: dup
B: clone
C: copy
D: None of the above. There is no way to make this code work.
Q15. Given the following code:
original = [[1,2],[3,4]]
copy = original.dup
original[0][0] = 42
p copy
Which option corresponds to the execution result? (Choose one.)
- A:
[[1,2],[3,4]] - B:
[[42,2],[3,4]] - C:
[[42],[3,4]] - D: A runtime error occurs.
Q16. Assume that the following code must have the stated execution result:
obj = Object.new
def obj.hello
puts "Hi!"
end
copy = __(1)__
copy.hello
[Execution Result]
Hi!
Which option can be inserted __(1)__ ? (Choose one.)
A: Marshal.load(Marshal.dump(obj))
B: obj.dup
C: obj.clone
D: obj.copy
Q17. Assume that the following code must have the stated execution result.
class ShoppingList
def initialize
@items = []
end
def add_item(item)
@items << item
end
def __(1)__
@items.map { |e| "- #{e} " }.join("\n")
end
end
list = ShoppingList.new
list.add_item("Milk")
list.add_item("Bread")
list.add_item("Eggs")
puts list
[Execution Result]
- Milk
- Bread
- Eggs
Which option can be inserted into __(1)__? (Choose one.)
A: to_s
B: to_str
C: inspect
D: puts
Q18. Assume that the following code must have the stated execution result.
class ShoppingList
def initialize
@items = []
end
def add_item(item)
@items << item
end
def __(1)__
"ShoppingList (##{object_id})\n @items: #{@items.inspect}"
end
end
list = ShoppingList.new
list.add_item("Milk")
list.add_item("Bread")
list.add_item("Eggs")
p list
[Execution Result]
ShoppingList (#70338683731980)
@items: ["Milk", "Bread", "Eggs"]
Which option can be inserted into __(1)__? (Choose one.)
A: to_s
B: to_str
C: inspect
D: p
Q19. Which of the following statements is true? (Choose one.)
A: Kernel#puts calls to_str on its arguments to produce a string representation.
B: Kernel#p calls to_str on its arguments to produce a string representation.
C: A default implementation of to_str is provided by Ruby's Object class
D: The to_str method is meant to be implemented only by objects that can behave similarly to String instances.
Q20. Given the following code:
a, b, c = ["apple", "banana", "carrot", "daikon"]
p c
Which option corresponds to the execution result?
A: ["apple", "banana", "carrot", "daikon"]
B: "carrot"
C: ["carrot"]
D: ["carrot", "daikon"]
Q21. Given the following code:
a, b, *c = ["apple", "banana", "carrot", "daikon"]
p c
Which option corresponds to the execution result?
A: ["apple", "banana", "carrot", "daikon"]
B: "carrot"
C: ["carrot"]
D: ["carrot", "daikon"]
Q22: Which code produces the following execution result? (Choose one.)
[Execution Result]
[["apple", "banana", "carrot"]]
A:
def fx(*args)
p(args)
end
fx(*["apple", "banana", "carrot"])
B:
def fx(*args)
p(args)
end
fx(["apple", "banana", "carrot"])
C:
def fx(*args)
p(args)
end
fx("apple", "banana", "carrot")
D:
def fx(*args)
p(*args)
end
fx(["apple", "banana", "carrot"])
Q23. Given the following code:
def add(x,y)
x + y
end
__(1)__
[Execution Result]
5
Which options can be inserted into __(1)__? (Choose two.)
A: p add(3,2)
B: p add(*[3,2])
C: p add([3,2])
D: p add(**[[3,2]])
Q24. Given the following code:
def fx(a:, b: "apple")
p a
p b
end
fx(b: "banana")
Which option corresponds to the execution result:
A:
nil
apple
B:
nil
banana
C: A syntax error occurs
D: An exception is raised
Q25. Assume that the following code must have the stated execution result.
def add(x:, y:, **params)
z = x + y
params[:round] ? z.round : z
end
__(1)__
[Execution Result]
7
Which option can be inserted into __(1)__? (Choose three.)
A: p add(x: 2.75, y: 5.25, round: true)
B: p add(x: 3.75, y: 3, round: true)
C: options = {:round => true}; p add(x: 3.75, y: 3, **options)
D: p add(x: 3, y: 4)
E: p add(x: 7)
Q26: Assume that the following code must have the stated execution result.
class Speaker
@message = "Hello!"
class << self
@message = "Howdy!"
def speak
@message
end
end
end
__(1)__
[Execution Result]
Hello!
Which options can be inserted into __(1)__? (Choose two.)
A: puts Speaker.speak
B: puts Speaker.singleton_class.speak
C: puts Speaker.instance_variable_get(:@message)
D: puts Speaker.singleton_class.instance_variable_get(:@message)
Q27. Given the following code:
class Speaker
@message = "Hello!"
class << self
@message = "Howdy!"
end
end
class << Speaker
p @message
end
Which option corresponds to the execution result? (Choose one.)
A: "Hello!"
B: "Howdy!"
C: nil
D: A syntax error is raised
Q28. Assume that the following code must have the stated execution result.
def x
puts "x"
end
def y
puts "y"
throw :done
end
def z
puts "z"
end
__(1)__ do
x
y
z
end
puts "done!"
[Execution Result]
x
y
done!
Which option can be inserted into __(1)__? (Choose one.)
A: try
B: catch
C: catch :done
D: rescue
Q29. Assume that the following code must have the stated execution result.
letters = catch(:done) do
("a".."z").each do |a|
("a".."z").each do |b|
("a".."z").each do |c|
if a < b && b < c
__(1)__
end
end
end
end
end
puts letters.join
[Execution Result]
abc
Which option can be inserted into __(1)__? (Choose one.)
A: throw [a,b,c]
B: throw [a,b,c], :done
C: throw :done, [a,b,c]
D: raise :done, [a,b,c]
Q30. Assume that the following code must have the stated execution result.
begin
raise __(1)__
rescue
puts "OK"
end
[Execution Result]
OK
Which option can be inserted into __(1)__? (Choose two.)
A: raise StandardError
B: raise Exception
C: raise ArgumentError
D: raise ScriptError
Q31. Given the following code:
AnError = Class.new(Exception)
begin
raise AnError
rescue
puts "Bare rescue"
rescue StandardError
puts "StandardError rescue"
rescue AnError
puts "AnError rescue"
rescue Exception
puts "Exception rescue"
end
Which option corresponds to the execution result? (Choose one.)
A:
Bare rescue
B:
StandardError rescue
C:
AnError rescue
D:
Exception rescue
E:
AnError rescue
Exception rescue
Q32. Given the following code:
AnError = Class.new(Exception)
begin
raise AnError
rescue
puts "Bare rescue"
rescue StandardError
puts "StandardError rescue"
rescue Exception
puts "Exception rescue"
rescue AnError
puts "AnError rescue"
end
Which option corresponds to the execution result? (Choose one.)
A:
Bare rescue
B:
StandardError rescue
C:
AnError rescue
D:
Exception rescue
E:
Exception rescue
AnError rescue
Q33. Given the following code:
begin
"hello".world
rescue => ex
p ex.class
end
Which option corresponds to the execution result? (Choose one.)
A: StandardError
B: Exception
C: NameError
D: NoMethodError
E: ArgumentError
Q34. Given the following code:
CustomError = Class.new(StandardError)
def boom
raise CustomError
rescue
raise
end
begin
boom
rescue => e
p e.class
end
Which option corresponds to the execution result? (Choose one.)
A: CustomError
B: StandardError
C: Exception
D: RuntimeError
E: SyntaxError
Q35. Given the following code:
def greeting
"hello"
ensure
puts "Ensured called!"
"hi"
end
puts greeting
Which option corresponds to the execution result? (Choose one.)
A:
hello
B:
hi
C:
Ensure called!
hello
D:
Ensure called!
hi
Q36. Given the following code:
class Identity
def self.this_object
self
end
def this_object
self
end
end
a = Identity.this_object
b = Identity.this_object
c = Identity.new.this_object
d = Identity.new.this_object
p a == b
p c == d
Which option corresponds to the execution result? (Choose one.)
A:
true
true
B:
true
false
C:
false
true
D:
false
false
Q37. Given the following code:
class Identity
def self.this_object
self.class
end
def this_object
self
end
end
p Identity.this_object.class
p Identity.new.this_object.class
Which option corresponds to the execution result? (Choose one.)
A:
Identity
Identity
B:
Class
Identity
C:
Object
Identity
D:
Class
Object
Q38. Given the following code:
module Mixin
def this_object
self
end
end
class Identity
include Mixin
end
p Identity.new.this_object.class
Which option corresponds to the execution result? (Choose one.)
A: Mixin
B: Class
C: Object
D: Identity
Q39: What is the direct superclass of the Class class? (choose one.)
A: Object
B: Module
C: BasicObject
D: Class
Q40. Given the following code:
module Mixin
def self.greet
puts "Hello World!"
end
end
class SomeClass
include Mixin
end
Which of the following statements is true? (Choose one.)
A: Mixin.greet will print Hello World!, SomeClass.greet will raise an exception.
B: Mixin.greet will raise an exception, SomeClass.greet will print Hello World!.
C: Both Mixin.greet and SomeClass.greet will print Hello World!.
D: Both Mixin.greet and SomeClass.greet will raise an exception.
Q41. Assume that the following code must have the stated execution result.
module Mixin
def greet
puts "Hello World!"
end
end
class SomeClass
extend Mixin
end
__(1)__
[Execution Result]
Hello World!
Which of the following options can be inserted into __(1)__? (Choose one.)
A:
Mixin.greet
B:
SomeClass.new.greet
C:
SomeClass.greet
D: Mixin.new.greet
Q42. Assume that the following code must have the stated execution result.
module Mixin
def greet
puts "Hello World!"
end
end
class SomeClass
include Mixin
end
__(1)__
[Execution Result]
Hello World!
Which of the following options can be inserted into __(1)__? (Choose one.)
A:
Mixin.greet
B:
SomeClass.new.greet
C:
SomeClass.greet
D: Mixin.new.greet
Q43. Assume that the following code must have the stated execution result.
class BaseClass
private
def greet
puts "Hello World!"
end
end
class ChildClass < BaseClass
__(1)__
end
ChildClass.new.greet
[Execution Result]
Hello World!
Which of the following options CANNOT be inserted into __(1)__? (Choose one.)
A:
public :greet
B:
protected :greet
C:
def greet
super
end
D:
alias_method :original_greet, :greet
def greet
original_greet
end
Q44. Assume that the following code must have the stated execution result:
class Upcaser
def initialize(value)
@value = value
end
def +(other)
self.class.new(@value + other.value)
end
def to_s
@value.upcase
end
attr_reader :value
__(1)__
end
puts Upcaser.new("Hello") + Upcaser.new("World")
[Execution Result]
HELLOWORLD
Which of the following options can be inserted into __(1)__? (Choose two.)
A: private :value
B: public :value
C: protected :value
D: static :value
Q45. Assume that the following code must have the stated execution result:
class Alphabet
include Enumerable
def initialize
@letters = ("A".."Z").to_a
end
def __(1)__
@letters.each do |e|
yield e
end
end
end
set = Alphabet.new
p set.take(5)
p set.select { |e| e > "W" }
[Execution Result]
["A", "B", "C", "D", "E"]
["X", "Y", "Z"]
Which of the following options can be inserted into __(1)__? (Choose one.)
A: all
B: each
C: to_a
D: to_ary
E: to_enum
Q46. Given the following code:
class TShirt
SIZES = [:xs, :s, :m, :l, :xl, :xxl]
include Comparable
def initialize(size)
@size = size
end
attr_reader :size
def <=>(other)
SIZES.index(size) <=> SIZES.index(other.size)
end
end
medium = TShirt.new(:m)
large = TShirt.new(:l)
p medium == large
p medium < large
p medium <= large
p medium > large
p medium >= large
Which option corresponds to the execution result? (Choose one.)
A:
true
false
true
false
true
B:
false
true
true
false
false
C:
false
false
false
true
true
D:
false
false
false
false
false
E: An exception is raised.
Q47. Given the following code:
require "date"
date = Date.new(2000, 2, 24)
puts(date << 12)
puts(date >> 12)
Which option corresponds to the execution result? (Choose one.)
A:
2000-02-12
2000-03-07
B:
2000-03-07
2000-02-12
C:
1999-02-24
2001-02-24
D:
1988-02-24
2012-02-24
Q48. Assume that the following code must have the stated execution result:
require "date"
d = Date.new(2000, 2, 18)
puts d __(1)__ 3
[Execution Result]
2000-02-21
Which option can be inserted into __(1)__? (Choose one.)
A: +
B: >>
C: <<
D: *
Q49. Assume that the following code reads the contents of the example.com homepage over HTTP:
__(1)__
puts open("http://example.com").read
What option can be inserted into __(1)__? (Choose one.)
A: require "uri"
B: require "net/http"
C: require "open3"
D: require "open-uri"
Q50. Assume that the following code must have the stated execution result:
if __(1)__ == "Henry"
puts "Hi Henry!!!"
else
puts "Hello, stranger."
end
[Execution Result]
Hi Henry!!!
Which option can be inserted into __(1)__? (Choose one.)
A: ENV['EMPLOYEE_NAME']
B: $env['EMPLOYEE_NAME']
C: ENV[:EMPLOYEE_NAME]
D: $env[:EMPLOYEE_NAME]