Ruby数组比较和排序

puts(p([1,2,3]<=>[2,3,4]))#=> -1 (array 1 < array 2)
puts(p([2,3,4]<=>[1,2,3])) #=> 1 (array 1 > array 2)
puts(p([1,2,3,4]<=>[1,2,3])) #=> 1 (array 1 > array 2)all
puts(p([1,2,3,4]<=>[100,200,300])) #=> -1 (array 1 < array 2)
puts(p([1,2,3]<=>["1","2","3"])) #=> nil (invalid comparison)

-1
-1
1
1
1
1
-1
-1
nil

arr = ['h','e','l','l','o',' ',nil,'w','o','r','l','d',1,2,3,nil,4,5]
# sort ascending from nil upwards
sorted_arr = arr.sort{
  |a,b|
  a.to_s <=> b.to_s
}
p(sorted_arr )

[nil, nil, " ", 1, 2, 3, 4, 5, "d", "e", "h", "l", "l", "l", "o", "o", "r", "w"]

reverse_sorted_arr = arr.sort{
  |a,b|
  b.to_s <=> a.to_s
}
p(reverse_sorted_arr )

["w", "r", "o", "o", "l", "l", "l", "h", "e", "d", 5, 4, 3, 2, 1, " ", nil, nil]

class MyArray < Array
  include Comparable
  def <=> ( anotherArray )
    self.length <=> anotherArray.length
  end
end
myarr1 = MyArray.new([0,1,2,3])
myarr2 = MyArray.new([1,2,3,4])
myarr1 <=> myarr2 #=> 0
puts(p( myarr1 < myarr2 )) #=> false
puts(p( myarr1 == myarr2 )) #=> true

false
false
true
true

开发环境:Rubymine

The book of Ruby----A hands-on guide for the Adventurous---[美]Huw Collingbourne---no starch press