rethinkdb - How to remove unnecessary field after grouping in rethinkdb, display just key-value pair?

Question

I got some result like this in rethinkdb using group

[  
   {  
      "group":[  
         0,
         "A"
      ],
      "reduction":14
   },
   {  
      "group":[  
         "B",
         0
      ],
      "reduction":2
   }
]

I used like r.....group(..).count() (I cannot mentioned all query because there are many steps). But my result should like be displayed like this:

[  
       {  
          "group":[  
             "A"
          ],
          "reduction":14
       },
       {  
          "group":[  
             "B"
          ],
          "reduction":2
       }
    ]

Even Better just key value pair [{"A":14},{"B":2}]

Answer 1

这不是世界上最干净的 ReQL，但它确实有效！

r.expr([  
   {  
      "group":[  
         0,
         "A"
      ],
      "reduction":14
   },
   {  
      "group":[  
         "B",
         0
      ],
      "reduction":2
   }
])
.map(function (row) {
  // Return a tuple with the key and the value
  return [row('group').filter(function (row) { return row.eq(0).not() }).nth(0), row('reduction') ]
})
.map(function (row) {
  // Convert the tuple into an array by passing an array of key-value pairs
  return r.expr([row]).coerceTo('object')
})

您可以将这两个地图功能结合起来，但我个人认为将它们分开会更好，以使它们更易于理解。

我使用过r.expr，因此您可以将其复制/粘贴到数据资源管理器中并查看它是否有效，但您可以maps在查询结束时复制/粘贴最后两个，结果将是相同的。

结果：

[
  {
    "A": 14
  } ,
  {
    "B": 2
  }
]