python如何鏈接hadoop，并且使用hadoop的資源，這篇文章介紹了一個簡單的案例！

一、python的map/reduce代碼

首先認為大家已經對haoop已經有了很多的了解，那么需要建立mapper和reducer，分別代碼如下：

1、mapper.py

#!/usr/bin/env python import sys for line in sys.stdin:line = line.strip()words = line.split()for word in words:print '%s\t%s' %(word, 1)

2、reducer.py

#!/usr/bin/env python from operator import itemgetter import syscurrent_word = None current_count = 0 word = Nonefor line in sys.stdin:words = line.strip()word, count = words.split('\t')try:count = int(count)except ValueError:continueif current_word == word:current_count += countelse:if current_word:print '%s\t%s' %(current_word, current_count)current_count = countcurrent_word = wordif current_word == word:print '%s\t%s' %(current_word, current_count)

建立了兩個代碼之后，測試一下：

[qiu.li@l-tdata5.tkt.cn6 /export/python]$ echo "I like python hadoop , hadoop very good" | ./mapper.py | sort -k 1,1 | ./reducer.py , 1 good 1 hadoop 2 I 1 like 1 python 1 very 1

二、上傳文件

發現沒啥問題，那么成功一半了，下面上傳幾個文件到hadoop做進一步測試。我在線上找了幾個文件，命令如下：

wget http://www.gutenberg.org/ebooks/20417.txt.utf-8 wget http://www.gutenberg.org/files/5000/5000-8.txt wget http://www.gutenberg.org/ebooks/4300.txt.utf-8

查看下載的文件：

[qiu.li@l-tdata5.tkt.cn6 /export/python]$ ls 20417.txt.utf-8 4300.txt.utf-8 5000-8.txt mapper.py reducer.py run.sh

上傳文件到hadoop上面，命令如下：hadoop dfs -put ./*.txt /user/ticketdev/tmp （hadoop是配置好的，目錄也是建立好的）

建立run.sh

hadoop jar $STREAM \-files ./mapper.py,./reducer.py \-mapper ./mapper.py \-reducer ./reducer.py \-input /user/ticketdev/tmp/*.txt \-output /user/ticketdev/tmp/output

查看結果：

[qiu.li@l-tdata5.tkt.cn6 /export/python]$ hadoop dfs -cat /user/ticketdev/tmp/output/part-00000 | sort -nk 2 | tail DEPRECATED: Use of this script to execute hdfs command is deprecated. Instead use the hdfs command for it.it 2387 which 2387 that 2668 a 3797 is 4097 to 5079 in 5226 and 7611 of 10388 the 20583

三、參考文獻：

http://www.cnblogs.com/wing1995/p/hadoop.html?utm_source=tuicool&utm_medium=referral

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