Update field instead of add to a field pymongo

Question

Whenever I try to update a field, it ends up adding the number to the field instead of replacing it. For example:

db.test.update_one({"_id": 0}, {'$inc': {"time": 2}})

If there were already 1 in the field time, the field time would update to 3 instead of 2. Can anyone help with this?

Does this answer your question? [How do I update a Mongo document after inserting it?](https://stackoverflow.com/questions/4372797/how-do-i-update-a-mongo-document-after-inserting-it) — whoami - fakeFaceTrueSoul, Apr 23 '20 at 05:25
max meinz : You might be missing something, `$set` will overwrite existing value doesn't increment it !! — whoami - fakeFaceTrueSoul, Apr 23 '20 at 05:38
post = {"coins":1} collection.update_one({'_id':1}, {"$set": post}, upsert=False) does not work. — HoneyPoop, Apr 23 '20 at 06:08

score 1 · Accepted Answer · answered Apr 23 '20 at 07:41

import pymongo
client = pymongo.MongoClient()
collection = client.testdb.test

print(collection.find_one())    # 'time': 1

collection.update_one( { '_id': 0 }, { '$set': { 'time': 3 } } )
print(collection.find_one())    #  'time': 4

collection.update_one( { '_id': 0 }, { '$inc': { 'time': 1 } } )
print(collection.find_one())    #  'time': 5

MongoDB document data can be updated with the update_one method. You can use different update operators for different update operations, e.g., $set, $inc, $unset, etc.

$inc Increments the value of the field by the specified amount.
$set Sets the value of a field in a document.

You can use any of the two above operators in your case. Note that $inc can be used with fields with numbers only.

Update field instead of add to a field pymongo

1 Answers1