如何根据每个数组中不超过某个总和的值将哈希拆分为多个键数组？

Question

我有一个大散列，其中键是名称，例如“Alex”，值是数字，例如“100”。 如何将此哈希拆分为包含键的多个数组，其中值的总和不超过某个阈值？

示例

我有哈希

{"Alex"=>50, "Bamby"=>100, "Jordan"=>300, "Ger"=>700, "Aus"=>500, "Can"=>360}

我想从一开始就将它分成 1000 包（不必从头开始，但会很好）， 意思：

array1 = ["Alex", "Bamby", "Jordan"] # not "Ger" bc it would exceed the 1000 in sum

array2 = ["Ger"] # not the Aus because it again would exceed the 1000

array3 = ["Aus", "Can"]

---

最好的解决方案实际上是对其进行优化，使代码使数组全部接近或等于 1000，但我猜这是下一步...

提前非常感谢您！ ~亚历克斯

Answer 1

h = {"Alex"=>50, "Bamby"=>100, "Jordan"=>300, "Ger"=>700, "Aus"=>500, "Can"=>360}

tot = 0
h.keys.slice_before { |k| (tot += h[k]) > 1000 ? tot = h[k] : false }.to_a
  #=> [["Alex", "Bamby", "Jordan"], ["Ger"], ["Aus", "Can"]]

如果tot > 1000 块返回一个真值（h[k]）并且tot += h[k] 周围的括号是必要的。

见Enumerable#slice_before。

Answer 2

original = {"Alex"=>50, "Bamby"=>100, "Jordan"=>300, "Ger"=>700, "Aus"=>500, "Can"=>360}

chunked = original.inject([]) do |array, (key, value)|
  array << {} unless array.any?

  if array.last.values.sum + value <= 1_000
    array.last.merge!(key => value)
  else
    array << { key => value }
  end

  array
end

# => [{"Alex"=>50, "Bamby"=>100, "Jordan"=>300}, {"Ger"=>700}, {"Aus"=>500, "Can"=>360}]

Answer 3

您可以像这样遍历散列中的元素，解释在 cmets 中：

hash={"Alex"=>50, "Bamby"=>100, "Jordan"=>300, "Ger"=>700, "Aus"=>500, "Can"=>360}
rs = [] # the outside array
rss = [] # the array inside the array
m = 0 # check if the sum of nexts are 1000
hash.each do |key, n|
  if m+n <= 1000  # if the counter + the next element < 1000
    m += n # then add it to the counter
    rss << key # add the key to the actual array
  else
    rs << rss #else m is equal or bigger than 1000, so, I add all the keys to the main array
    m=n # the element that overcomes m to 1000, becomes the first count now
    rss=[key] # And that key is the first element of a new array
  end
end
rs << rss #Importan! at the end, the final array need to be added outside the loop

print rs

结果_

=> [["Alex", "Bamby", "Jordan"], ["Ger"], ["Aus", "Can"]]