Question

我似乎无法找到计算数组中数组数量的算法。实施例

鉴于

[ [ "Array", "1" ], [ "Array", "2" ] ]

输出应该是两个

鉴于

[
    [
        [ ["Array", "1"], ["Array", "2"] ],
        [ ["Array", "3"], ["Array", "4"] ],
    ],
    [
        [ ["Array", "5"], ["Array", "6"] ],
        [ ["Array", "7"], ["Array", "8"] ]
    ]
]`

输出应为8

Answer 1

这个递归函数将为任何嵌套的数组执行任务：

def count_subarrays array
  return 0 unless array && array.is_a?(Array)

  nested = array.select { |e| e.is_a?(Array) }
  if nested.empty?
    1 # this is a leaf
  else
    nested.inject(0) { |sum, ary| sum + count_subarrays(ary) }
  end
end

Answer 2

我建议你使用一个递归函数，如果参数是一个叶子数组，它将返回1，例如：（如果每个阵列中有两个孩子，如saas课程练习）

 def array?(entity)
    entity[0].kind_of?(Array) ? array?(entity[0]) + array?(entity[1]) : 1
 end

Answer 3

class Array
  def deep_array_count()
    count = 0
    each{|el|
      #I could check with is_a?(Array), but with respond_to? you could use your own classes.
      if el.respond_to?(:deep_array_count)            
        count += 1 + el.deep_array_count
      end
    }
    count
  end
end

x = [
   [
     [
      ["Array", "1"], ["Array", "2"] ],
     [ ["Array", "3"], ["Array", "4"] ],
   ],
   [
     [ ["Array", "5"], ["Array", "6"] ],
     [ ["Array", "7"], ["Array", "8"] ]
   ]
  ]

 p x.deep_array_count

此示例中的结果为14，而不是您请求的8。我数每个数组。

要获得8，您必须只计算没有其他数组的数组。

class Array
  def deep_array_count()
    count = 0
    each{|el|
      #I could check with is_a?(Array), but with respond_to? you could use your own classes.
      if el.respond_to?(:deep_array_count)            
        i = el.deep_array_count
        count += i == 0 ? 1 : i #if no other array is inside, add 1
      end
    }
    count
  end
end

x = [
   [
     [
      ["Array", "1"], ["Array", "2"] ],
     [ ["Array", "3"], ["Array", "4"] ],
   ],
   [
     [ ["Array", "5"], ["Array", "6"] ],
     [ ["Array", "7"], ["Array", "8"] ]
   ]
  ]

 p x.deep_array_count

如何计算Ruby中数组中的数组数？

3 个答案: