ruby - 合并多个哈希数组并进行计算

Question

我有 2 个哈希数组:

charges = [
   {:created=>"2014-01-28", :charge=>43677}, 
   {:created=>"2014-01-29", :charge=>37980}, 
   {:created=>"2014-01-30", :charge=>87354}, 
   {:created=>"2014-01-31", :charge=>43677}
]

fees = [
   {:created=>"2014-01-28", :fee=>3230}, 
   {:created=>"2014-01-29", :fee=>2380}, 
   {:created=>"2014-01-30", :fee=>2210}, 
   {:created=>"2014-01-31", :fee=>1870}
]

我需要做的是获取费用并从每个日期的charges中减去它们并输出计算的金额，如下所示:

totals = [
   {:created=>"2014-01-28", :amount=>40447}, 
   {:created=>"2014-01-29", :amount=>35600}, 
   {:created=>"2014-01-30", :amount=>85144}, 
   {:created=>"2014-01-31", :amount=>41870}
]

请注意，特定日期可能不会总是既收费又收费。因此，在免费的情况下，您不会减去任何东西(或者您会减去 0)。在收费但不收费的情况下，您将得到一个负数。

Answer 1

我愿意

charges = [
   {:created=>"2014-01-28", :charge=>43677}, 
   {:created=>"2014-01-29", :charge=>37980}, 
   {:created=>"2014-01-30", :charge=>87354}, 
   {:created=>"2014-01-31", :charge=>43677}
]

fees = [
   {:created=>"2014-01-28", :fee=>3230}, 
   {:created=>"2014-01-29", :fee=>2380}, 
   {:created=>"2014-01-30", :fee=>2210}, 
   {:created=>"2014-01-31", :fee=>1870}
]

total = (fees + charges).group_by{ |h| h[:created] }.map do |k,v|
  val_hsh = v.each_with_object({}) do |h1,h2| 
    h1[:fee] ? h2[:fee] = h1[:fee] : h2[:charge] = h1[:charge]
  end
  {created: k, amount: val_hsh[:charge] - val_hsh[:fee]}
end

total 
# => [{:created=>"2014-01-28", :amount=>40447},
#     {:created=>"2014-01-29", :amount=>35600},
#     {:created=>"2014-01-30", :amount=>85144},
#     {:created=>"2014-01-31", :amount=>41807}]

更新

charges = [
   {:created=>"2014-01-28", :charge=>43677}, 
   {:created=>"2014-01-29", :charge=>37980}, 
   {:created=>"2014-01-30", :charge=>87354}, 
   {:created=>"2014-01-31", :charge=>0}
]

fees = [
   {:created=>"2014-01-28", :fee=>3230}, 
   {:created=>"2014-01-29", :fee=>0}, 
   {:created=>"2014-01-30", :fee=>2210}, 
   {:created=>"2014-01-31", :fee=>1870}
]

total = (fees + charges).group_by{ |h| h[:created] }.map do |k,v|
  val_hsh = v.each_with_object({}) do |h1,h2| 
    h1[:fee] ? h2[:fee] = h1[:fee] : h2[:charge] = h1[:charge]
  end
  {created: k, amount: val_hsh[:charge] - val_hsh[:fee]}
end

total 
# => [{:created=>"2014-01-28", :amount=>40447},
#     {:created=>"2014-01-29", :amount=>37980},
#     {:created=>"2014-01-30", :amount=>85144},
#     {:created=>"2014-01-31", :amount=>-1870}]