比较当前元素和剩余的数组（Ruby）

Question

我想将迭代中的当前元素与数组中其余元素进行比较。从起点看，我没有任何问题。这个问题出现在我想要比较当前元素与后面的元素之内。

array = [1, 2, 3, 2, 3, 4, 5] 


array.each_with_index do |num, index| 
    break if array[index + 1] == nil 
    if num > array[index + 1] 
    puts "#{num} is greater than the #{array[index + 1]}!" 
    else 
    puts "#{num} is less than the #{array[index + 1]}!" 
    end 
end 

我要寻找类似：

"3 is greater than 1 and 2 but less than 4 and 5" 

任何想法？

Answer 1

我假设你希望所有的数组中的元素相比，所以你可以不喜欢以下，通过制作Array#select使用：

array = [1, 2, 3, 2, 3, 4, 5] 
filtered_array = array.uniq 

array.each do |i| 
    greater_than = filtered_array.select { |comp| comp < i } 
    less_than = filtered_array.select { |comp| comp > i } 

    puts "#{i} is greater than #{greater_than} but less than #{less_than}" 
end 

你可以用格式化输出播放，但这将给：

1 is greater than [] but less than [2, 3, 4, 5] 
2 is greater than [1] but less than [3, 4, 5] 
3 is greater than [1, 2] but less than [4, 5] 
2 is greater than [1] but less than [3, 4, 5] 
3 is greater than [1, 2] but less than [4, 5] 
4 is greater than [1, 2, 3] but less than [5] 
5 is greater than [1, 2, 3, 4] but less than [] 

Answer 2

partition断裂分割了的元素分为两个独立的团体。

array = [1,2,3,4,5] 
array.each do |n| 
    less_than, greater_than = *(array - [n]).partition { |m| m <= n } 
    text = [] 
    text << "is greater than #{less_than.join(', ')}" if less_than.count > 0 
    text << "is less than #{greater_than.join(', ')}" if greater_than.count > 0 
    puts "#{n} #{text.join(' and ')}" 
end 

Answer 3

arr = [1, 2, 3, 2, 3, 4, 5] 

a = arr.uniq.sort 
    #=> [1, 2, 3, 4, 5] 
h = a.each_with_index.to_h 
    #=> {1=>0, 2=>1, 3=>2, 4=>3, 5=>4} 

arr.each { |i| puts "#{i} is greater than #{a[0,h[i]]} but less than #{a[h[i]+1..-1]}" } 

打印

1 is greater than [] but less than [2, 3, 4, 5] 
2 is greater than [1] but less than [3, 4, 5] 
3 is greater than [1, 2] but less than [4, 5] 
2 is greater than [1] but less than [3, 4, 5] 
3 is greater than [1, 2] but less than [4, 5] 
4 is greater than [1, 2, 3] but less than [5] 
5 is greater than [1, 2, 3, 4] but less than []