检查深度嵌套列表中的条件

如何解决检查深度嵌套列表中的条件

我正在使用MongoDB和PyMongo，并具有以下数据结构。

[
    {
        "position": 367,"entropy": 0.1327801096975522,"variants_flattened": [
            "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"
                ],"host": [
                    "Influenza A virus A/Xiamen/s200/2016","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
    }
]

根级别列表包含结构相似的多个对象。

我需要获取的实例（仅“序列”列表中的特定对象）的“ motif_short”等于“ I”。

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

{
                "position": 367,"Influenza A virus A/Xiamen/s228/2016"
                ]
}

我对MongoDB并不陌生，并且尝试了诸如Aggregate之类的一些选择，但是我是从哪里开始的。请帮帮我。

谢谢！

解决方法

您可以使用汇总$project和$filter解决此问题。对于这个特定问题，请尝试以下脚本：

#if col is our collection object in pymongo

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

此查询针对序列进行投影，并且对motif_short等于“ I”的过滤器进行过滤。结果，您将得到如下内容：

{
  "_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"
      ],"host":[
        "Influenza A virus A/Xiamen/s200/2016","Influenza A virus A/Xiamen/s228/2016"
      ]
    }
  ]
}