Round: Difference between revisions
From NoSQLZoo
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Rounding is easy inside a <code>MapReduce</code> as it is possible to use the <code>Math</code> object provided by JavaScript. | 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. | 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 | <div class=q data-lang="py3">MapReduce | ||
<pre class=def> | <pre class=def> | ||
Revision as of 12:55, 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
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"]
)