Difference between revisions of "Round"

Revision as of 13:55, 26 July 2015

#ENCODING
import io
import sys
sys.stdout = io.TextIOWrapper(sys.stdout.buffer, encoding='utf-16')
#MONGO
from pymongo import MongoClient
client = MongoClient()
client.progzoo.authenticate('scott','tiger')
db = client['progzoo']
#PRETTY
import pprint
pp = pprint.PrettyPrinter(indent=4)
#CODE
from bson.code import Code

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Rounding is easy inside a MapReduce as it is possible to use the Math object provided by JavaScript. At the time of writing the aggregation() method has no rounding functions, though it is still doable.

MapReduce

from bson.code import Code
temp = db.world.map_reduce(
        query={"population":{"$ne":None}},
        limit=1,
        map=Code("function(){emit(this.name, this.population)}"), 
        reduce=Code("function(key, values){return Math.round(values/1000000)}"),
        out={"inline":1},
)

pp.pprint(
   temp["results"]
)

@@ Line 18: / Line 18: @@
 Rounding is easy inside a <code>MapReduce</code> as it is possible to use the <code>Math</code> object provided by JavaScript.
 At the time of writing the <code>aggregation()</code> method has no rounding functions, though it is still doable.
+<div class='extra_space' style='width:1em; height:20em;'></div>
 <div class=q data-lang="py3">MapReduce
 <pre class=def>