removing [] and "" from array ruby on rails code example

Example 1: ruby remove value from array

# Altering the array:
a = [3, 2, 4, 6, 3, 8]
a.delete(3)
#=> 3
a
#=> [2, 4, 6, 8]

# Creating new array:
b = [3, 2, 4, 6, 3, 8]
b - [3]
#=> [2, 4, 6, 8]
b
#=> [3, 2, 4, 6, 3, 8]

Example 2: ruby array remove by index

a= [1,1,1,2,2,3]
delete_list = [1,3]
delete_list.each do |del|
    a.delete_at(a.index(del))
end