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I'm trying to use the sort feature when querying my mongoDB, but it is failing. The same query works in the MongoDB console but not here. Code is as follows:
import pymongo from pymongo import Connection connection = Connection() db = connection.myDB print db.posts.count() for post in db.posts.find({}, {'entities.user_mentions.screen_name':1}).sort({u'entities.user_mentions.screen_name':1}): print post The error I get is as follows:
Traceback (most recent call last): File "find_ow.py", line 7, in <module> for post in db.posts.find({}, {'entities.user_mentions.screen_name':1}).sort({'entities.user_mentions.screen_name':1},1): File "/Library/Python/2.6/site-packages/pymongo-2.0.1-py2.6-macosx-10.6-universal.egg/pymongo/cursor.py", line 430, in sort File "/Library/Python/2.6/site-packages/pymongo-2.0.1-py2.6-macosx-10.6-universal.egg/pymongo/helpers.py", line 67, in _index_document TypeError: first item in each key pair must be a string I found a link elsewhere that says I need to place a 'u' infront of the key if using pymongo, but that didn't work either. Anyone else get this to work or is this a bug.
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To sort the results of a query in ascending or, descending order pymongo provides the sort() method. To this method, pass a number value representing the number of documents you need in the result.
To sort documents in MongoDB, you need to use sort() method. The method accepts a document containing a list of fields along with their sorting order. To specify sorting order 1 and -1 are used. 1 is used for ascending order while -1 is used for descending order.
Use the sort() method to sort the result in ascending or descending order. The sort() method takes one parameter for "fieldname" and one parameter for "direction" (ascending is the default direction).
MongoDB can perform sort operations on a single-field index in ascending or descending order. In compound indexes, the sort order determines whether the index can be sorted. The sort keys must be listed in the same order as defined in the index.
.sort(), in pymongo, takes key and direction as parameters.
So if you want to sort by, let's say, id then you should .sort("_id", 1)
For multiple fields:
.sort([("field1", pymongo.ASCENDING), ("field2", pymongo.DESCENDING)]) If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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