从 ruby 中的哈希数组中获取唯一键值以执行分组答案

【问题标题】：get unique key values from an array of array of hash in ruby to perform grouping从 ruby 中的哈希数组中获取唯一键值以执行分组
【发布时间】：2021-08-19 11:27:17
【问题描述】：

我有一个数组如下：

arr = [
  [
    { :pm => 38, :scs => 5, :bg => "#66ffff", :impact => nil, :focus => 9 },
    { :pm => 38, :scs => 6, :bg => "#66ffff", :impact => 2, :focus => 9 },
    { :pm => 38, :scs => 7, :bg => "#66ffff", :impact => nil, :focus => 9 }
  ],
  [
    { :pm => 26, :scs => 5, :bg => "#ffe18b", :impact => 2, :focus => 2 },
    { :pm => 26, :scs => 6, :bg => "#ffe18b", :impact => 1, :focus => 2 },
    { :pm => 26, :scs => 7, :bg => "#ffe18b", :impact => nil, :focus => 2 }
  ],
  [
    { :pm => 39, :scs => 5, :bg => "#ffe18b", :impact => nil, :focus => 2 },
    { :pm => 39, :scs => 6, :bg => "#ffe18b", :impact => nil, :focus => 2 },
    { :pm => 39, :scs => 7, :bg => "#ffe18b", :impact => nil, :focus => 2 }
  ],
  [
    { :pm => 25, :scs => 5, :bg => "#ffffe5", :impact => 1, :focus => 4 },
    { :pm => 25, :scs => 6, :bg => "#ffffe5", :impact => 2, :focus => 4 },
    { :pm => 25, :scs => 7, :bg => "#ffffe5", :impact => 1, :focus => 4 }
  ],
  [
    { :pm => 34, :scs => 5, :bg => "#ffffe5", :impact => nil, :focus => 4 },
    { :pm => 34, :scs => 6, :bg => "#ffffe5", :impact => nil, :focus => 4 },
    { :pm => 34, :scs => 7, :bg => "#ffffe5", :impact => nil, :focus => 4 }
  ],
  [
    { :pm => 23, :scs => 5, :bg => "#ffffe5", :impact => 2, :focus => 4 },
    { :pm => 23, :scs => 6, :bg => "#ffffe5", :impact => 1, :focus => 4 },
    { :pm => 23, :scs => 7, :bg => "#ffffe5", :impact => 1, :focus => 4 }
  ],
  [
    { :pm => 32, :scs => 5, :bg => "#ffffe5", :impact => nil, :focus => 4 },
    { :pm => 32, :scs => 6, :bg => "#ffffe5", :impact => 2, :focus => 4 },
    { :pm => 32, :scs => 7, :bg => "#ffffe5", :impact => 1, :focus => 4 }
  ],
  [
    { :pm => 17, :scs => 5, :bg => "#ffffe5", :impact => nil, :focus => 4 },
    { :pm => 17, :scs => 6, :bg => "#ffffe5", :impact => 2, :focus => 4 },
    { :pm => 17, :scs => 7, :bg => "#ffffe5", :impact => 1, :focus => 4 }
  ]
]

我需要唯一地获取键:focus的值，以便根据焦点值对上述列表进行分组。

【问题讨论】：

您的预期结果是什么？

标签： arrays ruby-on-rails ruby hash

【解决方案1】：

这样可以吗？

arr.flatten.group_by {|elem| elem[:focus]}

如果您只需要 uniq focus 值，

arr.flatten.map {|elem| elem[:focus] }.uniq

【讨论】：