Pythonnoobはこちら。データベースの「data」というオブジェクトに次のものがあり、student_idの各グループから最低スコアを選択するPythonを作成し、見つかった最小レコードごとに一意のObjectIdを取得しますか?
{u'student_id': 197, u'_id': ObjectId('50906d7fa3c412bb040eb88d'), u'type': u'homework', u'score': 10.90872422518918}
{u'student_id': 197, u'_id': ObjectId('50906d7fa3c412bb040eb88e'), u'type': u'homework', u'score': 88.3871242475841}
{u'student_id': 198, u'_id': ObjectId('50906d7fa3c412bb040eb892'), u'type': u'homework', u'score': 17.46279901047208}
{u'student_id': 198, u'_id': ObjectId('50906d7fa3c412bb040eb891'), u'type': u'homework', u'score': 76.18366499496366}
{u'student_id': 199, u'_id': ObjectId('50906d7fa3c412bb040eb895'), u'type': u'homework', u'score': 49.34223066136407}
{u'student_id': 199, u'_id': ObjectId('50906d7fa3c412bb040eb896'), u'type': u'homework', u'score': 58.09608083191365}
お手数をおかけしますが....これが私のコードです...
import pymongo
from itertools import groupby
from pymongo import Connection
connection = Connection('localhost', 27017)
db = connection.students
data = db.grades.find({'type' : 'homework'}).sort([('student_id',pymongo.ASCENDING),('score',pymongo.ASCENDING)])
for student_id, items in groupby(data, lambda s: s['student_id']):
lowest_score = min(i['score'] for i in items)
print lowest_score