Compare array elements,remove the one with the lowest score - mongodb

Question

There are 200 documents in school db. I must remove each document which has "type":"homework" and the lowest score.
{
"_id" : 0,
"name" : "aimee Zank",
"scores" :
[
{
"type" : "exam",
"score" : 1.463179736705023
},
{
"type" : "quiz",
"score" : 11.78273309957772
},
{
"type" : "homework",
"score" : 6.676176060654615
},
{
"type" : "homework",
"score" : 35.8740349954354
}
]
}
For example,here
{
"type" : "homework",
"score" : 6.676176060654615
}
must be removed as score = 6.6 < 35.8
I sorted all the documents like this:
db.students.find({"scores.type":"homework"}).sort({"scores.score":1})
But I do not know how then to remove the doc having the lowest score and type:homework???
NOTE: how to solve it by not using aggregation method? E.g., by sorting and then updating.

Answer 1

This can be done in a couple of steps. The first step is to grab a list of the documents with the minimum score by using the aggregation framework with $match, $unwind and $group operators that streamlines your documents to find the minimum score for each document:
lowest_scores_docs = db.school.aggregate([
{ "$match": {"scores.type": "homework"} },
{ "$unwind": "$scores" }, { "$match": {"scores.type": "homework"} },
{ "$group": { "_id":"$_id", "lowest_score": {"$min": "$scores.score" } } } ] )
The second step is to loop through the dictionary above and use the $pull operator in the update query to remove the element from the array as follows:
for result in lowest_scores_docs["result"]:
db.school.update({ "_id": result["_id"] },
{ "$pull": { "scores": { "score": result["lowest_score"] } } } )

Answer 2

import pymongo
import sys
# connnecto to the db on standard port
connection = pymongo.MongoClient("mongodb://localhost")
db = connection.school # attach to db
students = db.students # specify the colllection
try:
cursor = students.find({})
print(type(cursor))
for doc in cursor:
hw_scores = []
for item in doc["scores"]:
if item["type"] == "homework":
hw_scores.append(item["score"])
hw_scores.sort()
hw_min = hw_scores[0]
#students.update({"_id": doc["_id"]},
# {"$pull":{"scores":{"score":hw_min}}})
except:
print ("Error trying to read collection:" + sys.exc_info()[0])