根据 Ruby Set 类的文档,“== 如果两个集合相等,则返回 true。每对元素的相等性是根据 Object#eql? 定义的。
其本质可以使用 Date 对象来演示,其中包含不同 Date 对象但具有相同日期的集合比较相等:
require 'set'
d1 = Date.today # => Thu, 30 Sep 2010
puts d1.object_id # => 2211539680
d2 = Date.today + 1 # => Fri, 01 Oct 2010
puts d2.object_id # => 2211522320
set1 = Set.new([d1, d2])
d11 = Date.today # => Thu, 30 Sep 2010
puts d11.object_id # => 2211489080
d12 = Date.today + 1 # => Fri, 01 Oct 2010
puts d12.object_id # => 2211469380
set2 = Set.new([d12, d11])
set1 == set2 # => true
但是使用我自己的对象,我在哪里编码了 eql?方法只比较某些属性,我无法让它工作。
class IpDet
attr_reader :ip, :gateway
def initialize(ip, gateway, netmask, reverse)
@ip = ip
@gateway = gateway
@netmask = netmask
@reverse = reverse
end
def eql?(other)
if @ip = other.ip && @gateway == other.gateway
return true
else
return false
end
end
end
ipdet1 = IpDet.new(123456, 123457, 123458, 'example.com')
ipdet2 = IpDet.new(234567, 2345699, 123458, 'nil')
ipdet11 = IpDet.new(123456, 123457, 777777, 'other_domain.com')
ipdet12 = IpDet.new(234567, 2345699, 777777, 'example.com')
puts "ipdet1 is equal to ipdet11: #{ipdet1.eql?(ipdet11)}"
puts "ipdet2 is equal to ipdet12: #{ipdet2.eql?(ipdet12)}"
set1 = Set.new([ipdet1, ipdet2])
set2 = Set.new([ipdet11, ipdet12])
puts "set 1 is equal to set2: #{set1 == set2}"
我从上面得到的输出是:
ipdet1 is equal to ipdet11: true
ipdet2 is equal to ipdet12: true
set 1 is equal to set2: false
有人有什么想法吗?