Question

我有一个哈希数组：

using Pkg

给出一定的数量，我想获取arr_of_hsh =[ {minimum_quantity: "250", cost: "1.5600"}, {minimum_quantity: "500", cost: "1.3500"}, {minimum_quantity: "1000", cost: "1.1800"}, {minimum_quantity: "2500", cost: "1.0200"} ]的值与小于或等于该数量的值最接近的哈希值。例如，如果数量为300，则将返回此哈希：

:minimum_quantity

，如果金额为1000：

{minimum_quantity: "250", cost: "1.5600"}

Answer 1

保持数据结构不变

 arr_of_hsh.select { |item| item[:minimum_quantity].to_i <= quantity }.
   max_by { |item| item[:minimum_quantity].to_i }

Answer 2

这里是单程解决方案。

def f(arr, qty)
  h = arr.min_by do |h|
    n = h[:minimum_quantity].to_i
    n <= qty ? (qty-n) : Float::INFINITY
  end
  h[:minimum_quantity].to_i <= qty ? h : nil 
end

(100..1100).step(100).each { |qty| puts "#{qty}: #{f(arr_of_hsh, qty)}" }
 100: nil
 200: nil
 300: {:minimum_quantity=>"250",  :cost=>"1.5600"}
 400: {:minimum_quantity=>"250",  :cost=>"1.5600"}
 500: {:minimum_quantity=>"500",  :cost=>"1.3500"}
 600: {:minimum_quantity=>"500",  :cost=>"1.3500"}
 700: {:minimum_quantity=>"500",  :cost=>"1.3500"}
 800: {:minimum_quantity=>"500",  :cost=>"1.3500"}
 900: {:minimum_quantity=>"500",  :cost=>"1.3500"}
1000: {:minimum_quantity=>"1000", :cost=>"1.1800"}
1100: {:minimum_quantity=>"1000", :cost=>"1.1800"}

如果要为给定的arr_of_hsh多次调用该方法，请按{em>减小值arr_of_hsh对arr_by_hsh[:minimum_quantity.to_i进行排序，然后简单地使用{{3 }}。

def f(arr, qty)
  h = arr.find { |h| h[:minimum_quantity].to_i <= qty }
end

arr = arr_of_hsh.sort_by { |h| -h[:minimum_quantity].to_i }
  #=> [{:minimum_quantity=>"2500", :cost=>"1.0200"},
  #    {:minimum_quantity=>"1000", :cost=>"1.1800"}, 
  #    {:minimum_quantity=>"500", :cost=>"1.3500"},
  #    {:minimum_quantity=>"250", :cost=>"1.5600"}]
(100..1100).step(100).each { |qty| puts "#{qty}: #{f(arr, qty)}" }
  #=> (same as above)

获取与最小数量匹配的哈希

2 个答案: