Question

我通过pymongo使用Python3查询我的Mongodb，我很难在响应中获得特定的嵌套字段。

正确返回所有“常规”字段，但嵌套的字段返回为无。

以下是我的数据集示例：

var listeners = {};

var originalEventListener = window.addEventListener;
window.addEventListener = function(type, fn, options) {
    if (!listeners[type])
        listeners[type] = [];

    listeners[type].push(fn);
    return originalEventListener(type, fn, options);
}

var removeAllEventListener = function(type) {
    if (!listeners[type] || !listeners[type].length)
        return;

    for (let i = 0; i < listeners[type].length; i++)
        window.removeEventListener(type, listeners[type][i]);
}

这是我的python代码的一部分：

{
    "_id":"5a8595ef93ccdb0f2301cf58",
    "docnum":"DOC001",
    "idcustomer":"CLI1",
    "customername":"Ringo",
    "address":[
        {
            "streetno":"45, First Avenue",
            "cityzip":"10001 New York"
        }],
    "totals":[
        {
            "totnetamnt":66.18,
            "totgrossamnt":86.034
        }]
}

这是我的当前输出，嵌套字段返回为无

import pymongo

from pymongo import MongoClient
client = MongoClient()

db = client.my_database

def load_data(db):
    cursor_docs = db.my_data.find(
        {
        " docnum " : " DOC0017133"
        }, 
        {
        "idcustomer" : 1,
        "docnum" : 1,
        "customername" : 1,
        "address.streetno" : 1,
        "address.cityzip" : 1,
        "totals.totnetamnt" : 1,
        "totals.totgrossamnt" : 1,
        }
        );

    #getting fields per document
    for docs in cursor_docs:
        docnum = docs.get("docnum")
        custname = docs.get("customername")
        address1 = docs.get("address.streetno")
        address2 = docs.get("address.cityzip")
        netamount =  docs.get("totals.totnetamnt")
        grossamount =  docs.get("totals.totgrossamnt")

        #checking field values
        print('docnum : ' + str(docnum))
        print('custname : ' + str(custname))
        print('address1 : ' + str(address1))
        print('address2 : ' + str(address2))
        print('netamount : ' + str(netamount))
        print('grossamount : ' + str(grossamount))

load_data(db)

这是我的预期输出，其中包含嵌套字段的实际值

docnum : DOC0017133
custname : Mary
address1 : None
address2 : None
netamount : None
grossamount : None

我尝试了不同的解决方案，但我总是将嵌套字段返回为无。

重点是：我如何只返回地址和总计的嵌套字段值（如上面的预期结果所示）？

Python - 如何从Mongodb中的文档返回嵌套字段的值？

0 个答案: