class CustomSorter
attr_accessor :start_date,:available
def initialize(start_date,available)
@start_date = Time.mktime(*start_date.split('-'))
@available = available
end
end
cs1 = CustomSorter.new('2015-08-01',2)
cs2 = CustomSorter.new('2015-08-02',1)
cs3 = CustomSorter.new('2016-01-01',1)
cs4 = CustomSorter.new('2015-02-01',3)
cs5 = CustomSorter.new('2015-03-01',4)
sorted = [cs1,cs2,cs3,cs4,cs5].sort_by { |cs| [Time.now <= cs.start_date,(cs.available || 0)] }
puts sorted.map(&:start_date)
但它失败了：
custom_sorter.rb:17:in `sort_by’: comparison of Array with Array Failed (ArgumentError)
解决方法
当排序算法比较创建的数组[Time.now< = cs.start_date,(cs.available || 0)]时,它会逐元素地对它们进行比较. 最初的元素是布尔值.没有为布尔定义订单.
irb(main):001:0> true <=> false => nil
你可以通过创建整数值来解决这个问题.
[cs1,cs5].sort_by { |cs| [Time.now <= cs.start_date ? 0 : 1,(cs.available || 0)] }