Question

此代码给出了一个错误：

TypeError：'CommandCursor'对象没有属性' getitem '

然而，当我的朋友在她的计算机上运行相同的代码时，她没有收到错误。我在Windows上使用Intel Pentium CPU。我有MongoDB运行（版本3.4），Python 2.7.13 :: Anaconda 4.3.1（64位）。

import json
import pymongo 
from bson import json_util
import re

FROM = "kenneth.lay@enron.com"

client = pymongo.MongoClient()
db = client.enron    
mbox = db.mbox

//Get the recipient lists for each message

recipients_per_message = db.mbox.aggregate([
{"$match" : {"From" : re.compile(r".*{0}.*".format(FROM), re.IGNORECASE)}}, 
{"$project" : {"From" : 1, "To" : 1} }, 
{"$group" : {"_id" : "$From", "recipients" : {"$addToSet" : "$To" } } }                    
])['result'][0]['recipients']

//The exact Error was:
TypeError Traceback (most recent call last) 
19 {"$project" : {"From" : 1, "To" : 1} },   
20 {"$group" : {"_id" : "$From", "recipients" : {"$addToSet":"$To" }}}  
---> 21 ])['result'][0]['recipients'] 
TypeError: 'CommandCursor' object has no attribute 'getitem'

Answer 1

你的朋友必须运行MongoDB和PyMongo的旧版本。从PyMongo 3.0开始，运行＆＃34;聚合＆＃34;使用PyMongo返回一个必须迭代结果的游标。试试这个：

results = list(db.mbox.aggregate([
    {"$match" : {"From" : re.compile(r".*{0}.*".format(FROM), re.IGNORECASE)}}, 
    {"$project" : {"From" : 1, "To" : 1} }, 
    {"$group" : {"_id" : "$From", "recipients" : {"$addToSet" : "$To" } } }                    
]))
recipients_per_message = results['result'][0]['recipients']

Python MongoDB聚合错误

1 个答案: