Mongodb map reduce tutorial [duplicate]

Question

Possible Duplicate:
How do I use Map/Reduce in MongoDB?

I have seen the MongoDb presentation for the new aggregation framework. There is a presentation, progressive examples etc...

Do you know something similar for map/reduce under MongoDB ?

I haven't found yet...

Answer 1

Check mongodb cookbook, you can see lot of map-reduce examples with good explanations.

Also check out my answer to other question in SO about mongo map reduce for more info.

Answer 2

This explain clarify map reduce for me: Yet another MongoDB Map Reduce tutorial

Answer 3

Check the documentation of map reduce for MongoDB. You find there a lot of examples.

The general form for mapReduce is this:

db.collection.mapReduce(
  <mapfunction>,
  <reducefunction>,
  {
      out: <collection>,
      query: <document>,
      sort: <document>,
      limit: <number>,
      finalize: <function>,
      scope: <document>,
      jsMode: <boolean>,
      verbose: <boolean>
  }
);