python编写mongodb中的map/reduce

Matthewl

#!/usr/bin/env python　　
# -*- encoding:utf-8 -*-
　　
from pymongo import Connection
　　
from bson.code import Code
　　
from bson.son import SON
　　
mongoconn = Connection('192.168.0.203',27017)
　　
db = mongoconn['things']["user_info"]
　　
db.drop()
　　
db.insert({"uid":"a123","type":"man","class":2,"score":{"math":80,"english":60,"chinese":90}})
　　
db.insert({"uid":"b123","type":"female","class":2,"score":{"math":100,"english":90,"chinese":80}})
　　
db.insert({"uid":"c123","type":"man","class":2,"score":{"math":60,"english":50,"chinese":88}})
　　
db.insert({"uid":"d123","type":"female","class":2,"score":{"math":79,"english":87,"chinese":78}})
　　
db.insert({"uid":"e123","type":"female","class":1,"score":{"math":79,"english":87,"chinese":78}})
　　
map = Code("function() {"
　　
"   emit(this.class,this.score);"
　　
"}"
　　
)
　　

　　
reduce = Code("function(key,values){"
　　
"    var result={math:0,english:0,chinese:0};"
　　
"   for (var i = 0; i < values.length; i++) {"
　　
"       result.math += values.math;"
　　
"       result.english += values.english;"
　　
"       result.chinese += values.chinese;"
　　
"   return result;"
　　
"}"
　　
)
　　
results = db.map_reduce(map,reduce,"class_user")
　　
a = db.find({"class":2})
　　
b = a.count()
　　
for i in results.find({"_id":2}):
　　
print "*********************************************************"
　　
print i
　　
print "math average score is :",i["value"]["math"]/b
　　
print "english average score is :",i["value"]["english"]/b
　　
print "chinese avarege score is :",i["value"]["chinese"]/b