Ruby Quiz Jan 2022

Question 1

What does %x!ls! represents?

Answer 1

Same as back tick command output ls

Question 2

What is the output?

>55.to_s(2)

Answer 2

“110111” - converts to binary

Question 3

What is the output?

0. nonzero?
1. nonzero?

Answer 3

nil
1

The nonzero?() is an inbuilt method in Ruby returns self if the number is non-zero, else it returns nil.

Question 4

def introduce1
__method__
end

def introduce2
__callee__
end

> introduce2
outout?

Answer 4

:introduce2

Question 5

colors = [“cyan”, “magenta”, “yellow”, “white”];
What is
>Hash[*colors]
will give?

Answer 5

{“cyan”=>”magenta”, “yellow”=>”white”}

Question 6

> a = [1,2,3,4]
_.to_s
_.class

what is the output?

Answer 6

“[1,2,3,4]”
String

_ repeats the last entered code in IRB

Question 7

What is the meaning of this code?

> %I[ Ruby is Cool]

Answer 7

[:Ruby, :is, :cool]

Interpolated Array of symbols, separated by whitespace

Question 8

Which one is correct?
%w(ruby is ok)
%i[ruby is ok]
%q{ruby is ok}
%r(ruby)

Answer 8

All are correct.these are non-alpha-numeric character delimiters:

 %w(ruby is ok)
 => ["ruby", "is", "ok"] 
3.0.0 :003 > %i[ruby is ok]
 => [:ruby, :is, :ok] 
3.0.0 :004 > %q{ruby is ok}
 => "ruby is ok" 
3.0.0 :005 > %r
 => /ruby is ok/ 
3.0.0 :006 >

Question 9

range = 1..Float::INFINITY

what would be the output?

Answer 9

=> 1..Infinity

Question 10

range = 1..Float::INFINITY

range.lazy.map { |x| x+x }.first(10)

Answer 10

=> [2, 4, 6, 8, 10, 12, 14, 16, 18, 20]

Question 11

array = %w(this is an array)
array * ‘ , ‘

What would be the output

Answer 11

=> “this, is, an, array”

join by

Question 12

How to get range values apart from entries method?

Answer 12

>p *(1..5)
1
2
3
4
5
=> [1, 2, 3, 4, 5]

Question 13

my_proc = -> argument { puts argument }
Which one is valid?
a)my_proc.call('hello')
b)my_proc.('hello')
c)my_proc['hello']

Answer 13

all are valid

Question 14

What would be the output?

> [*(‘a’..’e’)]

Answer 14

=> [“a”, “b”, “c”, “d”, “e”]

Question 15

Which delimiter is used to execute shell commands in ruby?

Answer 15

%x[ ] # Interpolated shell command