I am having difficulty in querying the follwing nested document using pymongo - mongodb

Question

If these are the following nested documents
[
{
"_id": 5,
"name": "Wilburn Spiess",
"scores": [
{
"score": 44.87186330181261,
"type": "exam"
},
{
"score": 25.72395114668016,
"type": "quiz"
},
{
"score": 63.42288310628662,
"type": "homework"
}
]
},
{
"_id": 6,
"name": "Jenette Flanders",
"scores": [
{
"score": 37.32285459166097,
"type": "exam"
},
{
"score": 28.32634976913737,
"type": "quiz"
},
{
"score": 81.57115318686338,
"type": "homework"
}
]
},
{
"_id": 7,
"name": "Salena Olmos",
"scores": [
{
"score": 90.37826509157176,
"type": "exam"
},
{
"score": 42.48780666956811,
"type": "quiz"
},
{
"score": 96.52986171633331,
"type": "homework"
}
]
}
]
I need to access the score part 'type' = exam.
Can somebody help me with this?

Answer 1

If you're asking for a python program to access the score, you can print them out like:
collection = mongo_connection['db']['collection']
documents = collection.find({})
for doc in documents:
for score in doc['scores']:
if score['type'] == 'exam':
print(f'Score: {score["score"]}')
If you are trying to retrieve only the scores and ignore the rest, I'd do an $unwind on the scores, $match on the type, and then project the fields you want (or not).
db.test.aggregate([
{
$unwind: '$scores'
},
{
$match: {
'scores.type': 'exam'
}
},
{
$project: {
'name': '$name',
'score': '$scores.score'
}
}
])
This would output:
{
"_id" : 5,
"name" : "Wilburn Spiess",
"score" : 44.8718633018126
},
{
"_id" : 6,
"name" : "Jenette Flanders",
"score" : 37.322854591661
},
{
"_id" : 7,
"name" : "Salena Olmos",
"score" : 90.3782650915718
}