How to sort mongodb with pymongo

Question

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  lt module gt      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

User · Answer

You can try this   db Account find   sort  UserName     db Account find   sort  UserName  pymongo ASCENDING     db Account find   sort  UserName  pymongo DESCENDING

User · Answer

This also works   db Account find   sort  UserName   -1  db Account find   sort  UserName   1    I m using this in my code  please comment if i m doing something wrong here  thanks

User · Answer

Why python uses list of tuples instead dict  In python  you cannot guarantee that the dictionary will be interpreted in the order you declared  So  in mongo shell you could do  sort   field1  1  field2  1   and the interpreter would sort field1 at first level and field 2 at second level  If this syntax was used in python  there is a chance of sorting by field2 at first level  With tuple  there is no such risk   sort    quot field1 quot  pymongo ASCENDING     quot field2 quot  pymongo DESCENDING

User · Answer

sort    field1  pymongo ASCENDING     field2  pymongo DESCENDING      Python uses key direction  You can use the above way   So in your case you can do this  for post in db posts find   sort  entities user mentions screen name  pymongo ASCENDING           print post

User · Answer

Say  you want to sort by  created on  field  then you can do like this    sort      format  created on    1 if sort type     asc  else -1

User · Answer

Sort by  id descending  collection find filter   quot keyword quot   keyword   sort     quot  id quot   -1      Sort by  id ascending  collection find filter   quot keyword quot   keyword   sort     quot  id quot   1

User · Answer

sort    in pymongo  takes key and direction as parameters  So if you want to sort by  let s say  id then you should  sort  quot  id quot   1  For multiple fields   sort    quot field1 quot   pymongo ASCENDING     quot field2 quot   pymongo DESCENDING

User · Answer

TLDR  Aggregation pipeline is faster as compared to conventional  find   sort     Now moving to the real explanation  There are two ways to perform sorting operations in MongoDB    Using  find   and  sort    Or using the aggregation pipeline    As suggested by many  find   sort   is the simplest way to perform the sorting    sort    field1  pymongo ASCENDING     field2  pymongo DESCENDING      However  this is a slow process compared to the aggregation pipeline    Coming to the aggregation pipeline method  The steps to implement simple aggregation pipeline intended for sorting are     match  optional step   sort   NOTE  In my experience  the aggregation pipeline works a bit faster than the  find   sort   method   Here s an example of the aggregation pipeline   db collection name aggregate          match               your query - optional step                  sort              field 1   pymongo ASCENDING           field 2   pymongo DESCENDING                           Try this method yourself  compare the speed and let me know about this in the comments   Edit  Do not forget to use allowDiskUse True while sorting on multiple fields otherwise it will throw an error

[python] How to sort mongodb with pymongo

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