Question

我有以下哈希列表：

[{"day":3,"count":2},{"day":1,"count":2},{"day":1,"count":2},{"day":2,"count":2},{"day":1,"count":2},{"day":4,"count":2},{"day":5,"count":2},{"day":6,"count":2},{"day":4,"count":2},{"day":4,"count":2},{"day":3,"count":2},{"day":3,"count":2},{"day":2,"count":2},{"day":6,"count":2},{"day":0,"count":2},{"day":5,"count":2},{"day":0,"count":2},{"day":5,"count":2},{"day":4,"count":2},{"day":1,"count":2},{"day":0,"count":2},{"day":0,"count":2},{"day":2,"count":2},{"day":2,"count":2},{"day":2,"count":2},{"day":1,"count":2},{"day":6,"count":2},{"day":5,"count":2},{"day":3,"count":2},{"day":2,"count":2},{"day":2,"count":2},{"day":1,"count":2},{"day":5,"count":2},{"day":4,"count":2},{"day":2,"count":2}]

我希望将具有相同“日期”值的所有密钥合并在一起，然后获得第二个键/值对的平均值的平均值。

例如，我的最终输出应如下所示：

[{"day":0, "count": 2}, {"day":1, "count": 2}, {"day":3, "count": 2}, {"day":4, "count": 2}, {"day":5, "count": 2}, {"day":6, "count": 2}, {"day":7, "count": 2},]

计算平均值实际上是计算的（并非总是“2”），我只是以两个为例。

Answer 1

# group the list into sublists sharing the same day
data.group_by { |element| element['day'] }.map { |day, element_list|
  # for each day, return a new object
  {
    day:   day,
    # extract the count from all the elements in the sublist,
    # then add them together and divide by number of elements
    # (convert to float to avoid integral division)
    count: element_list.map { |element| element['count'] }.
             reduce(:+).to_f / element_list.size
  }
}

Answer 2

如果您的哈希集合被称为data：

，这将有效

days = data.group_by{|record| record["day"] }
days.map do |day, records|
  {day: day, count: records.map{|record| record["count"] }.average}
end

Ruby Merge列表哈希＆amp;获得平均值

2 个答案: