mongodb, pymongo querying

I've been browsing through the documentation, but I can't seem to figure out a way to perform a find on my mongodb collection using only a key.开发者_如何学Go For example, let's suppose this is what's inside my collection

{ 'res1': 10 }
{ 'res2: 20 }

How can I query the collection using only the key 'res1', in order to get 10 ?

Not sure exaclty what you want, so... This is if you want all documents that have key res1 set:

db.collection.find({'res1': { $exists : true }})

And this is if you want all the documents that have key res1 set to 10:

db.collection.find({'res1': 10})

Ah, I guess I'm structuring my data all wrong, I should have something like this:

{ 'name': 'res1',
  'value': 10 }

Right?

> db.collection.find({'res1': 10}) # Returns a cursor.

In your case, find_one method will do the needful.

> db.collection.find_one({'res1': 10}) # Returns a document whose value is 10