Question

I am trying to figure out a way to iterate through and remove duplicate records from four different sources.

first_source = [#<Customer:0x007f911e307ad0 @id="123", @name="Whitehall">,#       <Customer:0x007f911e307ad0 @id="124", @name="Whitehall">#<Customer:0x007f911e307ad0 @id="125", @name="Whitehall">]
second_source =  [#<Customer:0x007f911e307ad0 @id="5000", @name="Whitehall">,#<Customer:0x007f911e307ad0 @id="5500", @name="Whitehall">#<Customer:0x007f911e307ad0 @id="123", @name="Whitehall">]
third_source =  [#<Customer:0x007f911e307ad0 @id="800", @name="Whitehall">,#<Customer:0x007f911e307ad0 @id="5000", @name="Whitehall">#<Customer:0x007f911e307ad0 @id="124", @name="Whitehall">]
fourth_source =  [#<Customer:0x007f911e307ad0 @id="4300", @name="Whitehall">,#<Customer:0x007f911e307ad0 @id="800", @name="Whitehall">#<Customer:0x007f911e307ad0 @id="125", @name="Whitehall">]

I tried

customers = []

dup_customers = first_source + second_source + third_source + fourth_source

dup_customers.combination(2).each do |cs1, cs2|
  customers << cs1 unless cs1.id != cs2.id
end

But this really did not work.

Can someone help me suggest a way/strategy for traversing through these four collections and finding the Customer id’s that are equal and then doing something with it?

Answer 1

How about Array#uniq?

customers = (first_source + second_source + third_source + fourth_source).uniq

uniq discards duplicates by element-wise comparison using Object#eql?, so for this method to work, you would need to implement Customer#eql?.

class Customer
  def eql?(other)
    id == other.id #or however you define equality
  end
end