如果 0 后跟 >=1 从 MongoDB 中的数组中删除 0 值 [英] remove 0 values if 0 is followed by >=1 from arrays in MongoDB

问题描述

在 data_start 中，如果 0 后跟 >=1 则从 data_start 中删除 0，同时从 time_start相应的数组.

<预><代码>{数据开始":[1、1、0,0,1、1、0],时间开始":[2021-09-04T12:18:42Z"，2021-09-04T14:59:50Z"，2021-09-04T14:59:59Z"，2021-09-04T15:00:00Z"，2021-09-04T15:00:01Z"，2021-09-04T15:05:00Z"，2021-09-04T15:05:01Z"]}

输出文件将是:

<代码>{数据开始":[1、1、0,1、1、0],时间开始":[2021-09-04T12:18:42Z"，2021-09-04T14:59:50Z"，2021-09-04T14:59:59Z"，2021-09-04T15:00:01Z"，2021-09-04T15:05:00Z"，2021-09-04T15:05:01Z"]}

解决方案

一种方法是这样的:

db.collection.aggregate([{$set:{数据: {$let: {变量:{val:$data_start"，prev: { $concatArrays: [[null], "$data_start"] }//将值移动一个元素},在: {$地图:{输入:{ $range: [0, { $size: "$$val";}] },如:idx"，在: {$cond: {如果: {$和:[{ $eq: [{ $arrayElemAt: ["$$val", "$$idx"] }, 0] },//是 0{ $eq: [{ $arrayElemAt: ["$$val", "$$idx"] }, { $arrayElemAt: ["$$prev", "$$idx"] }] }//等于之前]},然后:空，别的: {data_start: { $arrayElemAt: ["$$val", "$$idx"] },time_start: { $arrayElemAt: ["$time_start", "$$idx"] }}}}}}}}}},{$set:{数据: {$过滤器:{输入:$数据"，条件:$$this"//->从数组中删除空值}}}}])

也许您必须微调条件和/或反转循环，即 input: { $range: [{ $size: "$$val"}, 0, -1] }

Mongo 游乐场

In data_start if 0 is followed by >=1 in the array then remove the 0 from the data_start , also remove the element from time_start array accordingly.

{
  "data_start": [
    1,
    1,
    0,
    0,
    1,
    1,
    0
  ],
  "time_start": [
    "2021-09-04T12:18:42Z",
    "2021-09-04T14:59:50Z",
    "2021-09-04T14:59:59Z",
    "2021-09-04T15:00:00Z",
    "2021-09-04T15:00:01Z",
    "2021-09-04T15:05:00Z",
    "2021-09-04T15:05:01Z"
  ]
}

Output Document will be :

{
"data_start": [
    1,
    1,
    0,
    1,
    1,
    0
  ],
  "time_start": [
    "2021-09-04T12:18:42Z",
    "2021-09-04T14:59:50Z",
    "2021-09-04T14:59:59Z",
    "2021-09-04T15:00:01Z",
    "2021-09-04T15:05:00Z",
    "2021-09-04T15:05:01Z"
  ]
}

解决方案

One approach is this one:

db.collection.aggregate([
   {
      $set: {
         data: {
            $let: {
               vars: {
                  val: "$data_start",
                  prev: { $concatArrays: [[null], "$data_start"] } // shift values by one element 
               },
               in: {
                  $map: {
                     input: { $range: [0, { $size: "$$val" }] },
                     as: "idx",
                     in: {
                        $cond: {
                           if: {
                              $and: [
                                 { $eq: [{ $arrayElemAt: ["$$val", "$$idx"] }, 0] }, // is 0
                                 { $eq: [{ $arrayElemAt: ["$$val", "$$idx"] }, { $arrayElemAt: ["$$prev", "$$idx"] }] } // is equal to previous
                              ]
                           },
                           then: null,
                           else: {
                              data_start: { $arrayElemAt: ["$$val", "$$idx"] },
                              time_start: { $arrayElemAt: ["$time_start", "$$idx"] }
                           }
                        }
                     }
                  }
               }
            }
         }
      }
   },
   {
      $set: {
         data: {
            $filter: {
               input: "$data",
               cond: "$$this"// -> removes null's from array
            }
         }
      }
   }
])

Maybe you have to fine-tune the condition and/or reverse the loop, i.e. input: { $range: [{ $size: "$$val" }, 0, -1] }

Mongo playground

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