Fastest way to find a String into an array of string

The script has to verify if one predefined IP is present in a big array of IPs. Currently I code that function like this (saying that "ips" is my array of IP and "ip" is the predefined ip)

ips.each do |existsip|
  if ip == existsip
    puts "ip exists"
    return 1
  end
end
puts "ip doesn't exist"
return nil

Is there a faster way to do the same thing?

Edit : I might have wrongly expressed myself. I can do array.include? but what I'd like to know is : Is array.include? the method that will give me the fastest result?