Ruby on Rails – Hash of Arrays，group by和sum by many columns
我有一个类似的问题，这个主题Ruby on Rails – Hash of Arrays，group by和sum by column name
但是，我的问题是group by和sum by with many columns而不是one。
例如：我的哈希
[ {"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"} ] 结果是这样的
[ {"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"} ]
像这样的group_hashes arr, ["order","order1"], ["money","money1"]
我在合并中尝试了一个循环！ 但结果是错误的。 请教我解决这个案子。 抱歉我的愚蠢思想。
Usnig Enumerable#group_by ，您可以迭代按order ， order1键分组的哈希数组。
然后合并哈希（通过总结money ， money1条目）：
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 }