# -*- coding: utf-8 -*-
import os
import csv
import pymongo
from pymongo import MongoClient
from bson.code import Code
from pymongo import MongoClient
#建立连接
client = MongoClient(‘10.20.4.79‘, 27017)
#client = MongoClient(‘10.20.66.106‘, 27017)
db_name = ‘ta‘ #数据库名
db = client[db_name]
插入测试数据：
for i in xrange(1000):
rID=math.floor(random.random()*10);
price = round(random.random()*10,2);
if rID < 4:
db.test.insert({"_id":i,"user":"Joe","product":rID,"price":price});
elif rID>=4 and rID<7:
db.test.insert({"_id":i,"user":"Josh","product":rID,"price":price});
else:
db.test.insert({"_id":i,"user":"Ken","product":rID,"price":price});
结果数据为：
{ "_id" : 0, "price" : 5.9, "product" : 9, "user" : "Ken" }
{ "_id" : 1, "price" : 7.59, "product" : 7, "user" : "Ken" }
{ "_id" : 2, "price" : 4.72, "product" : 0, "user" : "Joe" }
{ "_id" : 3, "price" : 1.35, "product" : 1, "user" : "Joe" }
{ "_id" : 4, "price" : 2.31, "product" : 0, "user" : "Joe" }
{ "_id" : 5, "price" : 5.29, "product" : 5, "user" : "Josh" }
{ "_id" : 6, "price" : 3.34, "product" : 1, "user" : "Joe" }
{ "_id" : 7, "price" : 7.2, "product" : 4, "user" : "Josh" }
{ "_id" : 8, "price" : 8.1, "product" : 6, "user" : "Josh" }
{ "_id" : 9, "price" : 2.57, "product" : 3, "user" : "Joe" }
{ "_id" : 10, "price" : 0.54, "product" : 2, "user" : "Joe" }
{ "_id" : 11, "price" : 0.66, "product" : 1, "user" : "Joe" }
{ "_id" : 12, "price" : 5.51, "product" : 1, "user" : "Joe" }
{ "_id" : 13, "price" : 3.74, "product" : 6, "user" : "Josh" }
{ "_id" : 14, "price" : 4.82, "product" : 0, "user" : "Joe" }
{ "_id" : 15, "price" : 9.79, "product" : 3, "user" : "Joe" }
{ "_id" : 16, "price" : 9.6, "product" : 5, "user" : "Josh" }
{ "_id" : 17, "price" : 4.06, "product" : 7, "user" : "Ken" }
{ "_id" : 18, "price" : 1.37, "product" : 5, "user" : "Josh" }
{ "_id" : 19, "price" : 6.77, "product" : 9, "user" : "Ken" }
测试1、每个用户各购买了多少个产品？用SQL语句实现为：select user,count(product) from test group by user
mapper = Code("""function (){emit(this.user,{count:1})}""")
reduce = Code("function (key, values) {"
" var total = 0;"
" for (var i = 0; i < values.length; i++) {"
" total += values[i].count;"
" }"
" return {count:total};"
"}")
result=db.test.map_reduce(mapper,reduce,out =‘myresults‘)
for doc in db.myresults.find():
print doc
测试 2、查询每个用户，买了多少商品，总价格，及评价价格 条件是价格大于5的 SQL实现：select user,count(sku),sum(price)，
round(sum(price)/count(sku),2) as avgPrice from test where prince>5 group by user
mapper=Code("""function (){emit(this.user,{amount:this.price,count:1,avgPrice:0})}""")
reduce = Code("function (key, values) {"
" var res={amount:0,count:0,avgPrice:0};"
" for (var i = 0; i < values.length; i++) "
" {"
" res.count += values[i].count;"
" res.amount += values[i].amount;"
" }"
" res.avgPrice = (res.amount/res.count).toFixed(2);"
" return res;"
"}")
result = db.test.map_reduce(mapper,reduce,out =‘myresults‘,query={‘price‘:{‘$gt‘: 6}})
for doc in db.myresults.find():
print doc