检查深层嵌套列表中的条件

Question

我使用的是MongoDB和PyMongo，数据结构如下。

[
    {
        "position": 367,
        "entropy": 0.1327801096975522,
        "variants_flattened": [
            "GFRHQNSEG",
            "GFRHQNSEG",
            "GFRHQNSEG",
            "GFRHQNAEG"
        ],
        "supports": 51,
        "sequences": [
            {
                "position": 367,
                "sequence": "GFRHQNSEG",
                "count": 50,
                "conservation": 98.03921568627452,
                "motif_short": "I",
                "motif_long": "Index",
                "id": [
                    "APQ31289.1",
                    "ASU55526.1",
                    "ASU55528.1",
                    "APQ31291.1"
                ],
                "strain": [
                    "Influenza A virus A/Xiamen/s200/2016",
                    "Influenza A virus A/Shandong-Zhifu/164/2016",
                    "Influenza A virus A/Shandong-Zhifu/1185/2016",
                    "Influenza A virus A/Xiamen/s228/2016"
                ],
                "country": [
                    "HA Hemagglutinin",
                    "HA Hemagglutinin",
                    "HA Hemagglutinin",
                    "HA Hemagglutinin"
                ],
                "host": [
                    "Influenza A virus A/Xiamen/s200/2016",
                    "Influenza A virus A/Shandong-Zhifu/164/2016",
                    "Influenza A virus A/Shandong-Zhifu/1185/2016",
                    "Influenza A virus A/Xiamen/s228/2016"
                ]
            },
            {
                "position": 367,
                "sequence": "GFRHQNAEG",
                "count": 1,
                "conservation": 1.9607843137254902,
                "motif_short": "Ma",
                "motif_long": "Major",
                "id": [
                    "QBM69728.1"
                ],
                "strain": [
                    "Influenza A virus A/China/70793/2016"
                ],
                "country": [
                    "HA Hemagglutinin"
                ],
                "host": [
                    "Influenza A virus A/China/70793/2016"
                ]
            }
        ],
        "variants": 2
    }
]

根级别列表包含多个结构相似的对象。

我需要的是获取"motif_short“等于"I”的实例(仅来自"sequences“列表中的特定对象)。

预期输出为(在此特定示例中，只有一个输出对象，但在单个实例中可以有多个符合此条件的对象)：

{
                "position": 367,
                "sequence": "GFRHQNSEG",
                "count": 50,
                "conservation": 98.03921568627452,
                "motif_short": "I",
                "motif_long": "Index",
                "id": [
                    "APQ31289.1",
                    "ASU55526.1",
                    "ASU55528.1",
                    "APQ31291.1"
                ],
                "strain": [
                    "Influenza A virus A/Xiamen/s200/2016",
                    "Influenza A virus A/Shandong-Zhifu/164/2016",
                    "Influenza A virus A/Shandong-Zhifu/1185/2016",
                    "Influenza A virus A/Xiamen/s228/2016"
                ],
                "country": [
                    "HA Hemagglutinin",
                    "HA Hemagglutinin",
                    "HA Hemagglutinin",
                    "HA Hemagglutinin"
                ],
                "host": [
                    "Influenza A virus A/Xiamen/s200/2016",
                    "Influenza A virus A/Shandong-Zhifu/164/2016",
                    "Influenza A virus A/Shandong-Zhifu/1185/2016",
                    "Influenza A virus A/Xiamen/s228/2016"
                ]
}

我是MongoDB的新手，已经尝试过一些选项，比如聚合，但这正是我开始的地方。请帮帮我。

提前感谢！

Answer 1

您可以使用聚合$project和$filter来解决此问题。请尝试使用以下脚本来解决此特定问题：

#if col is our collection object in pymongo

result = col.aggregate([{'$project': {'sequences': { '$filter': { 'input': '$sequences', 'as': 's', 'cond': { '$eq': ['$$s.motif_short', 'I'] } } } }}])

此查询在motif_short等于"I“的序列和过滤器上进行投影。你会得到类似这样的结果：

{
  "_id":"xyz",
  "sequences":[
    {
      "position":367,
      "sequence":"GFRHQNSEG",
      "count":50,
      "conservation":98.03921568627452,
      "motif_short":"I",
      "motif_long":"Index",
      "id":[
        "APQ31289.1",
        "ASU55526.1",
        "ASU55528.1",
        "APQ31291.1"
      ],
      "strain":[
        "Influenza A virus A/Xiamen/s200/2016",
        "Influenza A virus A/Shandong-Zhifu/164/2016",
        "Influenza A virus A/Shandong-Zhifu/1185/2016",
        "Influenza A virus A/Xiamen/s228/2016"
      ],
      "country":[
        "HA Hemagglutinin",
        "HA Hemagglutinin",
        "HA Hemagglutinin",
        "HA Hemagglutinin"
      ],
      "host":[
        "Influenza A virus A/Xiamen/s200/2016",
        "Influenza A virus A/Shandong-Zhifu/164/2016",
        "Influenza A virus A/Shandong-Zhifu/1185/2016",
        "Influenza A virus A/Xiamen/s228/2016"
      ]
    }
  ]
}