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1.What does the `group_by` method do in Ruby Enumerables?

Filters elements based on a regular expression.

Groups elements based on a given block and returns a hash.

Sorts the elements in ascending order.

Counts the occurrences of a specific element.

2.How can you check if all elements in an Enumerable are positive numbers?

all?(&:positive?)

every?{|e| e.positive?}

positive?{|e| e.all?}

is_positive?{|e| e}

3.What does the `flat_map` method do in Ruby Enumerables?

Splits the collection into two equal parts.

Groups consecutive elements based on a given block.

Transforms each element using a block and flattens the result into a single array.

Counts the occurrences of a specific element.

4.How can you find the index of the minimum element in an Enumerable?

index

min_index

find_index

min

5.What will the output be for the following code?

arr = [1, 2, 3, 4, 5]
result = arr.each_with_index.map { |x, i| x * i }
puts result.join(',')

0,2,6,12,20

1,2,3,4,5

0,1,4,9,16

1,4,9,16,25

6.What is the purpose of the `each_with_object` method in Enumerables?

Transforms each element using a block.

Iterates over each element and accumulates a result with an initial object.

Counts the occurrences of a specific element.

Returns the last element in the collection.

7.How do you find the difference between two Enumerables in Ruby?

difference

diff

subtract

minus

8.How can you convert an Enumerable of key-value pairs into a hash in Ruby?

convert_to_hash

hashify

to_h

to_hash

9.What does the `one?` method do in Enumerables?

Checks if exactly one element in the collection satisfies a given condition.

Checks if all elements in the collection satisfy a given condition.

Counts the number of elements in the collection.

Returns true if there is only one element in the collection.

10.How can you find the last n elements in an Enumerable?

last(n)

tail(n)

end(n)

take_last(n)

11.What is the purpose of the `chunk_while` method in Enumerables?

Splits the collection into two equal parts.

Groups consecutive elements based on a given block until the block condition is false.

Counts the occurrences of a specific element.

Transforms each element using a block.

12.What will the output be for the following code?

arr = [1, 2, 3, 4, 5]
result = arr.inject { |sum, x| sum * x }
puts result

120

15

30

0

13.How do you remove all occurrences of a specific element from an Enumerable?

delete{|e| e == specific_element}

exclude{|e| e == specific_element}

remove{|e| e == specific_element}

reject{|e| e == specific_element}

14.What does the `each_slice` method do in Enumerables?

Reverses the order of the collection.

Slices the collection into two equal parts.

Iterates over the collection in slices of a given size.

Transforms each element using a block.

15.How do you find the intersection of two Enumerables in Ruby?

intersection

intersect

common

&

16.What does the `sum` method do in Ruby Enumerables?

Calculates the sum of all elements in the collection.

Counts the occurrences of a specific element.

Returns the last element in the collection.

Finds the maximum value in the collection.

17.What does the `slice_before` method do in Enumerables?

Groups consecutive elements based on a given block.

Slices the collection before a given element.

Returns the last element in the collection.

Shuffles the elements randomly.

18.How do you select and return elements from an Enumerable based on their index positions?

positions_at

indices_at

select_at

values_at

19.What is the purpose of the `reverse_each` method in Enumerables?

Counts the occurrences of a specific element in reverse order.

Reverses the order of the elements in the collection.

Transforms each element using a block in reverse order.

Iterates over the collection in reverse order.

20.What is the result of the following code?

arr = [1, 2, 3, 4, 5]
result = arr.cycle(3).take_while { |x| x < 10 }.to_a
puts result.join(',')

1,2,3,4,5,1,2,3,4,5,1,2,3,4,5

1,2,3,4,5,6,7,8,9,10

1,2,3,4,5,1,2,3

1,2,3,4,5

Enumerables V