Enumerator is a type of class which allows both the internal and external iteration.

List Of Enumerable Methods in Ruby:

• collect
• map
• each 
• select

Collect:

It is similar to the map method and it allows us to iterate through the elements of the collection.

For Example:

x = [1,2,3,4]
y = x.collect{|a| 2*a}
puts y

# y = [2,4,6,8]

Map:

It iterates through a collection of array , performs a specific action on that array and returns the array.

For Example:

x = [2,4,6,8]
x.map do |y|
  y*2
end

# x = [4,8,12,16]

Each:

It returns all the elements of an array or hash.

For Example:

x = ["bike","cycle","car"]
x.each do |y|
  puts y
end


# x = ["bike","cycle","car"]

Select:

It allows us to select elements from a group of elements.

x = [1,2,3,4,5,6,7,8,9]
x.select |y|
  y >= 3 && y <= 8
end


# x = [3,4,5,6,7,8]