Ruby on Rails的 - 通过阵列，组​​哈希和多列通过总结 [英] Ruby on Rails - Hash of Arrays, group by and sum by with many columns

问题描述

我有这个问题类似的问题
<一href=\"http://stackoverflow.com/questions/8500280/ruby-on-rails-hash-of-arrays-group-by-and-sum-by-column-name\">Ruby on Rails的 - 通过阵列，组​​哈希和金额列名

I have a similar problem with this topic Ruby on Rails - Hash of Arrays, group by and sum by column name

不过，我的问题是，通过和群组多列，而不是一个通过总结

However, my problem is that group by and sum by with many columns instead of one.

例如：我的哈希值

[
    {"idx"=>"1234", "account"=>"abde", "money"=>"4.00", "money1"=>"1.00", "order"=>"00001", "order1"=>"1"},
    {"idx"=>"1235", "account"=>"abde", "money"=>"2.00", "money1"=>"1.00", "order"=>"00001", "order1"=>"1"},
    {"idx"=>"1235", "account"=>"abde", "money"=>"3.00", "money1"=>"1.00", "order"=>"00002", "order1"=>"2"}
]

这样的结果。

[
    {"idx"=>"1234", "account"=>"abde", "money"=>"6.00", "money1"=>"2.00","order"=>"00001", "order1"=>"1"},
    {"idx"=>"1234", "account"=>"abde", "money"=>"3.00", "money1"=>"1.00","order"=>"00002", "order1"=>"2"}
]

这样的调用 group_hashes改编，[秩序，order1]，[钱，MONEY1]

我试过一个循环内合并！但是，结果是错误的。
请告诉我解决这个情况。对不起，我的心中蠢

I tried a loop inside merge! However, the result is wrong. Please teach me solve this case. Sorry for my stupid mind.

推荐答案

Usnig的 可枚举＃GROUP_BY ，则可以通过迭代订单，<$ C组合哈希数组$ C> order1 键。

Usnig Enumerable#group_by, you can iterate arrays of hashes grouped by order, order1 key.

然后合并哈希（通过总结钱， MONEY1 项）：

Then merge hashes (by summing up money, money1 entries):

a = [
  {"idx"=>"1234", "account"=>"abde", "money"=>"4.00", "money1"=>"1.00", "order"=>"00001", "order1"=>"1"},
  {"idx"=>"1235", "account"=>"abde", "money"=>"2.00", "money1"=>"1.00", "order"=>"00001", "order1"=>"1"},
  {"idx"=>"1235", "account"=>"abde", "money"=>"3.00", "money1"=>"1.00", "order"=>"00002", "order1"=>"2"}
]
a.group_by { |x| x.values_at('order', 'order1') }.map {|key, hashes|
  result = hashes[0].clone
  ['money', 'money1'].each { |key|
    result[key] = hashes.inject(0) { |s, x| s + x[key].to_f }
  }
  result
}
# => [{"idx"=>"1234", "account"=>"abde", "money"=>6.0, "money1"=>2.0, "order"=>"00001", "order1"=>"1"},
#     {"idx"=>"1235", "account"=>"abde", "money"=>3.0, "money1"=>1.0, "order"=>"00002", "order1"=>"2"}]

---

group_keys = ['order', 'order1']
sum_keys = ['money', 'money1']
a.group_by { |x| x.values_at(*group_keys) }.map {|key, hashes|
  result = hashes[0].clone
  sum_keys.each { |key|
    result[key] = hashes.inject(0) { |s, x| s + x[key].to_f }
  }
  result
}

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