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Today, I will talk to you about the example analysis of MongoDB in R language. Many people may not understand it very well. In order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.

R Sword MongeDB, divided into four chapters.

MongoDB environment preparation

Rmongodb function library

Basic operation of rmongodb

Rmongodb test case

Each chapter is divided into a "text description section" and a "code section" to keep the text description consistent with the code.

1. MongoDB environment preparation

Text description part:

First of all, the environment is prepared. Here I choose the 32-bit desktop version of Linux Ubuntu operating system 12.04. you can choose the convenient Linux according to your usage habits.

The MongoDB installation process is skipped.

View the MongoDB server environment

Use the mongod command to start MongoDB.

Process number: pid=2924

Port: port=27017

Data file directory: dbpath=/data/db/

Software version: 32-bit

Hostname: host=conan

Use the mongo command to open mongo shell.

Simple operation of mongo shell:

View the database, switch the database, view the dataset.

R language environment 2.15.0 WinXP accesses Mongodb Server through remote connection.

Code part:

View the operating system

~ uname-a

Linux conan 3.2.0-38-generic-pae # 61-Ubuntu SMP Tue Feb 19 12:39:51 UTC 2013 i686 i686 i386 GNU/Linux

~ cat / etc/issue

Ubuntu 12.04.2 LTS\ n\ l

Start mongodb

~ mongod

Mongod-help for help and startup options

Thu Apr 11 11:02:26

Thu Apr 11 11:02:26 warning: 32-bit servers don't have journaling enabled by default. Please use-- journal if you want durability.

Thu Apr 11 11:02:26

Thu Apr 11 11:02:26 [initandlisten] MongoDB starting: pid=2924 port=27017 dbpath=/data/db/ 32-bit host=conan

Thu Apr 11 11:02:26 [initandlisten]

Thu Apr 11 11:02:26 [initandlisten] * * NOTE: when using MongoDB 32 bit, you are limited to about 2 gigabytes of data

Thu Apr 11 11:02:26 [initandlisten] * * see http://blog.mongodb.org/post/137788967/32-bit-limitations

Thu Apr 11 11:02:26 [initandlisten] * * with-journal, the limit is lower

Thu Apr 11 11:02:26 [initandlisten]

Thu Apr 11 11:02:26 [initandlisten] db version v2.0.6, pdfile version 4.5

Thu Apr 11 11:02:26 [initandlisten] git version: e1c0cbc25863f6356aa4e31375add7bb49fb05bc

Thu Apr 11 11:02:26 [initandlisten] build info: Linux domU-12-31-39-01-70-B4 2.6.21.7-2.fc8xen # 1 SMP Fri Feb 15 12:39:36 EST 2008 i686 BOOST_LIB_VERSION=1_41

Thu Apr 11 11:02:26 [initandlisten] options: {}

Thu Apr 11 11:02:26 [websvr] admin web console waiting for connections on port 28017

Thu Apr 11 11:02:26 [initandlisten] waiting for connections on port 27017

Open mongo shell

~ mongo

MongoDB shell version: 2.0.6

Connecting to: test

Enter mongo shell and list the database

> show dbs

Db 0.0625GB

Feed 0.0625GB

Foobar 0.0625GB

Local (empty)

Switch database

> use foobar

Switched to db foobar

List display dataset

> show collections

Blog

System.indexes

R language development environment 2.15.0 WinXP

~ r

R version 2.15.0 (2012-03-30)

Copyright (C) 2012 The R Foundation for Statistical Computing

ISBN 3-900051-07-0

Platform: i386-pc-mingw32/i386 (32-bit)

2. Rmongodb function library

Text description part:

Rmongodb has developed a large number of functions corresponding to the operation of mongo. Compared with other NoSQL, it is really a huge project. But I always feel that the encapsulation granularity is not enough, and it is more complicated to write code.

All the rmongodb function libraries are listed below, and I'll just pick a few commonly used introductions.

Establish a mongo connection

Mongo

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