MongoDB: update dictionary in document

from mongoDb website look at "Set Fields in Embedded Documents"

To specify a <field> in an embedded document or in an array, use dot notation.For the document matching the criteria _id equal to 100, the followingoperation updates the make field in the details document:db.products.update({ _id: 100 },{ $set: { "details.make": "zzz" } })

in your case

db.collection.update(     {_id:ObjectId("1")},     { $set: { "occurrences.12": "3", "occurrences.17": "2" }})

I wrote a function to convert a dictionary to a new dictionary which only updates fields in that dictionary:

def convert_2_dict_mongodb(obj):    result = {}    for key, val in obj.items():        if not isinstance(val, dict):            result[key] = val            continue        for sub_key, sub_val in val.items():            new_key = '{}.{}'.format(key, sub_key)            result[new_key] = sub_val            if not isinstance(sub_val, dict):                continue            result.update(convert_2_dict_mongodb(result))            if new_key in result:                del result[new_key]    return result

Example:

abc = {    'a': 1,    'b': {        'x': 1,        'y': 2,        'z': {            'g': 1,            'h': {                'e': [1, 2, 3]            }        }    },    'h': {        'a': [1, 2, 3]    }}

To:

{'h.a': [1, 2, 3], 'b.x': 1, 'b.z.h.e': [1, 2, 3], 'b.z.g': 1, 'a': 1, 'b.y': 2}