Ruby on rails 带散列的和数组

如何在这两个散列数组之间执行加法，例如，我想从第一个数组中提取第一个散列，然后求和

number、s\u number、l\u number

，如果从第二个数组中提取第一个散列，那么求和将取决于在

处创建的
，如果在第一个数组中创建的
与在第二个数组中创建的
相等，则执行
+
。请看一下我期望得到的回报，因为我不知道如何更好地解释这一点

多谢各位

raw_data = [
        [
            {"created_at"=>"2013-11-17","number"=>0,"s_number"=>0,"l_number"=>0},
            {"created_at"=>"2013-11-18","number"=>6,"s_number"=>1,"l_number"=>4},
            {"created_at"=>"2013-11-19","number"=>1,"s_number"=>1,"l_number"=>1},
            {"created_at"=>"2013-11-20","number"=>0,"s_number"=>0,"l_number"=>0}
        ],
        [
            {"created_at"=>"2013-11-17","number"=>2,"s_number"=>3,"l_number"=>4},
            {"created_at"=>"2013-11-18","number"=>1,"s_number"=>41,"l_number"=>1},
            {"created_at"=>"2013-11-19","number"=>5,"s_number"=>45,"l_number"=>7},
            {"created_at"=>"2013-11-20","number"=>7,"s_number"=>8,"l_number"=>2}    
        ]
        ]

应该退还什么

[
        {"created_at"=>"2013-11-17","number"=>2,"s_number"=>3,"l_number"=>4},
        {"created_at"=>"2013-11-18","number"=>7,"s_number"=>42,"l_number"=>5},
        {"created_at"=>"2013-11-19","number"=>6,"s_number"=>46"l_number"=>8},
        {"created_at"=>"2013-11-20","number"=>7,"s_number"=>8,"l_number"=>2}    
]

更新哈希格式与我发布的不同：

{:created_at=>Sun, 17 Nov 2013, :number=>0, :s_number=>0, :l_number=>0}

我会这样做：

result = raw_data.flatten.each_with_object({}) do |hash, result|
  date = hash.delete("created_at")
  result[date] = Hash.new(0) unless result[date]
  hash.each{|key, val| result[date][key] += val}
end.map{|date, hash| hash["created_at"] = date; hash}

p result #=> [{"number"=>2, "s_number"=>3, "l_number"=>4, "created_at"=>"2013-11-17"}, ...

或者更好，因为它将保持哈希的顺序：

result = raw_data.flatten.group_by{|x|x["created_at"]}.values.map do |x| 
  x.inject do |result, hash| 
    result.merge(hash){|key, old, new| old.is_a?(String) ? old : old + new }
  end
end

p result #=> [{"created_at"=>"2013-11-17", "number"=>2, "s_number"=>3, "l_number"=>4},  {"created_at"=>"2013-11-18", "number"=>7, "s_number"=>42, "l_number"=>5} ...

首先，需要对数组求和：

raw_data.sum

这将返回类似于：

    [
        {"created_at"=>"2013-11-17","number"=>0,"s_number"=>0,"l_number"=>0},
        {"created_at"=>"2013-11-18","number"=>6,"s_number"=>1,"l_number"=>4},
        {"created_at"=>"2013-11-19","number"=>1,"s_number"=>1,"l_number"=>1},
        {"created_at"=>"2013-11-20","number"=>0,"s_number"=>0,"l_number"=>0}
        {"created_at"=>"2013-11-17","number"=>2,"s_number"=>3,"l_number"=>4},
        {"created_at"=>"2013-11-18","number"=>1,"s_number"=>41,"l_number"=>1},
        {"created_at"=>"2013-11-19","number"=>5,"s_number"=>45,"l_number"=>7},
        {"created_at"=>"2013-11-20","number"=>7,"s_number"=>8,"l_number"=>2}    
    ]

现在，我们需要按“created_at”键对元素进行分组：

raw_data.sum.group_by{|element| element['created_at']}

这将导致：

{
    "2013-11-17" => [
        {"created_at"=>"2013-11-17","number"=>0,"s_number"=>0,"l_number"=>0},
        {"created_at"=>"2013-11-17","number"=>2,"s_number"=>3,"l_number"=>4},
      ],
    "2013-11-18" => [
        {"created_at"=>"2013-11-18","number"=>6,"s_number"=>1,"l_number"=>4},
        {"created_at"=>"2013-11-18","number"=>1,"s_number"=>41,"l_number"=>1}
      ], ...           
}

我们只需要此散列的值：

raw_data.sum.group_by{|element| element['created_at']}.values

# =>
    [
      [
        {"created_at"=>"2013-11-17","number"=>0,"s_number"=>0,"l_number"=>0},
        {"created_at"=>"2013-11-17","number"=>2,"s_number"=>3,"l_number"=>4},
      ],
      [
        {"created_at"=>"2013-11-18","number"=>6,"s_number"=>1,"l_number"=>4},
        {"created_at"=>"2013-11-18","number"=>1,"s_number"=>41,"l_number"=>1}
      ], ...           
}

现在我们需要将每个散列数组映射到一个散列。为此，我们将使用块的注入和合并函数：

raw_data.sum.group_by{|element| element[:created_at]}.values.map{|a| a.inject({}) {|result, hash| result.merge(hash) {|key, old_value, new_value| key == :created_at ? old_value : old_value + new_value}}}



# =>

[
    {"created_at"=>"2013-11-17","number"=>2,"s_number"=>3,"l_number"=>4},
    {"created_at"=>"2013-11-18","number"=>7,"s_number"=>42,"l_number"=>5},
    {"created_at"=>"2013-11-19","number"=>6,"s_number"=>46"l_number"=>8},
    {"created_at"=>"2013-11-20","number"=>7,"s_number"=>8,"l_number"=>2}    
]

output=[]
raw_data.flatte.group_by{x | x[：created_at].to_s}。每个do |键，值|
temp_hash={:created_at=>key.to_date}
[：编号，：s_编号，：l_编号]。每个do|attr|
temp|u hash[attr]=value.collect{w|w[attr]}.sum
结束
输出尝试下一个代码：

result = raw_data.flatten.group_by{|x|x["created_at"]}.values.map do |x| 
  x.inject do |result, hash| 
    result.merge(hash){|key, old, new| old.is_a?(String) ? old : old + new }
  end
end

对于您提供的第一个答案数据，我得到了以下错误：
Date不能强制为Fixnum
，对于第二个：
预期为数字
，因此如果日期存储为日期而不是字符串，请将最后一个答案中的
old.is_a？（string）
更改为old.is_a？（Date）我这样做了，但做了一些奇怪的事情：
[{“created\u at”：“2013-11-17”，“编号”：103，“s_编号”：102，“l_编号”：87}]
这就是你从上述原始数据中得到的吗？这看起来真的很奇怪？有人知道吗？我想问题出在这里，我从另一个地方获取了数组格式，显然，这就是我的日期发送方式<代码>{:created_at=>Sun，2013年11月17日，：number=>0，：s_number=>0…}
如果您在
irb
中运行上述代码，那么您可能会得到未定义的方法sum，但它在rails控制台中工作。如果您想在纯ruby中运行它，那么只需将
sum
替换为
reduce（：+）
like
temp_hash[attr]=值。收集{w | w[attr]}。reduce（：+）
如果您得到的是未定义的方法
sum
或
+
，那么您的哈希值必须是
{u在2013-11-18”，“number”=>“7”处创建的字符串，“s|u number”=>“42”、“l|u number”=>“5”}
。如果这是问题所在，那么您可以简单地使用
temp|u hash[attr]=值。收集{w | w[attr]。to|i}.sum
或
temp|u hash[attr]=值。收集{w | w[attr]。to|i}.reduce（：）
现在正在为散列中的每个元素返回null。请检查我的更新。谢谢
没有将数组隐式转换为散列
我现在得到了这个…
预期的数字
我昨天也遇到了同样的情况，请检查此链接：>
def sum_two_arrays_of_hashes(raw_data, keys = %w[number s_number l_number])
  raw_data[0].map.with_index do |item, index|
    if raw_data[1][index]["created_at"] = item["created_at"]
      sum_hash = {}
      sum_hash["created_at"] = item["created_at"]
      sum_hash.merge keys.inject({}){ |m, k| m[k] = raw_data[1][index][k] + item[k];  m}
    end
  end
end

result = raw_data.flatten.group_by{|x|x["created_at"]}.values.map do |x| 
  x.inject do |result, hash| 
    result.merge(hash){|key, old, new| old.is_a?(String) ? old : old + new }
  end
end