My goal:
calculate:
"open" * 1.1
before pymongo output the data, because I think it would be faster
Data looks like following:
{
"_id": "000016.XSHE_2020-01-02-09-32",
"order_book_id": "000016.XSHE",
"datetime": {
"$date": "2020-01-02T09:32:00.000Z"
},
"num_trades": 0,
"low": 4.3131,
"close": 4.3228,
"high": 4.3326,
"total_turnover": 2826041,
"volume": 639124,
"open": 4.3228
}
{
"_id": "000016.XSHE_2020-01-02-09-33",
"order_book_id": "000016.XSHE",
"datetime": {
"$date": "2020-01-02T09:33:00.000Z"
},
"num_trades": 0,
"low": 4.3131,
"close": 4.3228,
"high": 4.3326,
"total_turnover": 1087488,
"volume": 246300,
"open": 4.3131
}....
I am trying the following codes but none working:
tdcursor = MinutesDB.find({"order_book_id": "000016.XSHE", "datetime": {"$gte": recent11TradingDays[-1]},
"uplimit":{"$multiply":{"open": 1.1}}},
{"_id": 0, "order_book_id":1, "datetime": 1, "open": 1, "close": 1})
datadf = pd.DataFrame(tdcursor)
or
multiply = MinutesDB.aggregate([
{"$group":
{"order_book_id": "000016.XSHE",
"uplimit": {"$multiply": ["$open", 1.1]}
}
}
])
datadf = pd.DataFrame(multiply)
the code above gives error like below:
pymongo.errors.OperationFailure: The $in accumulator is a unary operator, full error: {'ok': 0.0, 'errmsg': 'The $in accumulator is a unary operator', 'code': 40237, 'codeName': 'Location40237'}
Thanks for your help!
here is a solution with an aggregate
db.collection.aggregate([
{
"$match": {
"order_book_id": "000016.XSHE",
}
},
{
"$project": {
"uplimit": {
"$multiply": [
"$open",
1.1
]
}
}
}
])
Since you wand to query only the documents that match : order_book_id": "000016.XSHE, you will need a $matchstage in the aggregate
And then a $projectto use the $multiply
Try it here