gistfile1.rb

input_array = [1, 2, 1, 4, 1.0, 1r]

require 'set'
Set.new(input_array).to_a
# => [1, 2, 4, 1.0, (1/1)]

unique_elements = []
input_array.each { |el| unique_elements << el unless unique_elements.include?(el) }
unique_elements
# => [1, 2, 4]

unique_elements = {}
input_array.each { |el| unique_elements[el.hash] = el unless unique_elements.key?(el.hash) }
unique_elements.values
# => [1, 2, 4, 1.0, (1/1)]