如何拆分Ruby哈希数组

Question

我想拆分哈希数组。

.split没有处理它。

我希望在保持顺序的同时将其拆分为两个，因此可能.partion，.select，group_by对我不起作用。

来自此的东西

allay = [
  {name: "Iron Man", power: "Tech"},
  {name: "Spiderman", power: "Iron Man as Uncle"},
  {name: "Thor", power: "God"},
  {name: "Hawk Eye", power: "None"},
  {name: "Black Widow", power: "love her"}
]

以此作为输出

=> [
  [
    {name: "Iron Man", power: "Tech"},
    {name: "Spiderman", power: "Iron Man as an Uncle"},
    {name: "Thor", power: "God"}
  ],
  [
    {name: "Hawk Eye", power: "None"},
    {name: "Black Widow", power: "love her <3"}
  ]
]

Answer 1

您可以使用Enumerable#each_slice来获得所需的行为：

left, right = allay
  .each_slice(allay.length.succ / 2)
  .to_a

当然，还有其他方法可以做到这一点，但它们并不是那么好。这是另一个：

pivot = allay.length.succ / 2
left, right = allay
  .partition
  .with_index { |_, i| i < pivot }

另一个：

left, right = [], allay.dup
left << right.shift until left.length >= right.length

基准！

      each_slice    785.207k (± 5.6%) i/s -      3.920M in   5.006885s
      with_index    694.555k (± 6.6%) i/s -      3.474M in   5.023968s
      push_shift      1.674M (± 6.2%) i/s -      8.343M in   5.004380s
       take_drop      3.468M (± 6.8%) i/s -     17.303M in   5.013369s

Answer 2

可以使用drop和take：

来实现

def split_by_index(array, n)
  [array.take(n), array.drop(n)]
end

Answer 3

您可以对范围使用[]表示法。

arr = [*1..6]
s = arr.size
[arr[0..s/2-1], arr[s/2..-1]]
 #=> [[1, 2, 3], [4, 5, 6]]

arr = [*1..7]
s = arr.size
[arr[0..s/2-1], arr[s/2..-1]]
 #=> [[1, 2, 3], [4, 5, 6, 7]]