在这里,我们假设把文件保存到hadoop-0.20.2/test/code/reducer.py AI检测代码解析 #!/usr/bin/env python from operator import itemgetter import sys current_word = None current_count = 0 word = None for line in sys.stdin: line = line.strip() word, count = line.split('\t', 1) try: coun...
我们唯一需要做的是利用Python的sys.stdin读取输入数据,并把我们的输出传送给sys.stdout。Hadoop流将会帮助我们处理别的任何事情。1.1 Map阶段:mapper.py在这里,我们假设把文件保存到hadoop-0.20.2/test/code/mapper.py#!/usr/bin/env python import sys for line in sys.stdin: line = line.strip() words = ...
hduser_@andrew-PC:/home/andrew/code/HadoopWithPython/python/MapReduce/HadoopStreaming$ $HADOOP_HOME/bin/hadoop jar $HADOOP_HOME/share/hadoop/tools/lib/hadoop-streaming-2.9.2.jar -files mapper.py,reducer.py -mapper mapper.py -reducer reducer.py -input /user/hduser/input2.txt -output /user/...
命令:cat word.txt | python mapper.py >运行reducer.py 命令: cat word.txt | python mapper.py | sort -k1,1 | python reducer.py 我们可以看到映射器和减速器按预期工作,因此我们不会面临任何进一步的问题。 在Hadoop 上运行Python 代码 在我们在 Hadoop 上运行 MapReduce 任务之前,将本地数据(word.txt...
下面我们来看看,通过python如何完成这里的 Map 和 Reduce 阶段。 2.1 Map阶段:mapper.py 在这里,我们假设map阶段使用到的python脚本存放地址为 ShowMeAI/hadoop/code/mapper.py 代码语言:python 代码运行次数:0 运行 AI代码解释 #!/usr/bin/env python import sys for line in sys.stdin: line = line.strip(...
#!/usr/bin/python 18/02/26 15:36:49 INFO mapreduce.Job: Task Id : attempt_1519366762440_0020_m_000000_2, Status : FAILED Error: java.lang.RuntimeException: PipeMapRed.waitOutputThreads(): subprocess failed with code 127 at org.apache.hadoop.streaming.PipeMapRed.waitOutputThreads(PipeMapRed...
hduser_@andrew-PC:/home/andrew/code/HadoopWithPython/python/MapReduce/HadoopStreaming$ $HADOOP_HOME/bin/hadoop jar $HADOOP_HOME/share/hadoop/tools/lib/hadoop-streaming-2.9.2.jar -files mapper.py,reducer.py -mapper mapper.py -reducer reducer.py -input/user/hduser/input2.txt -output /user/...
Code Issues Pull requests Data science Python notebooks: Deep learning (TensorFlow, Theano, Caffe, Keras), scikit-learn, Kaggle, big data (Spark, Hadoop MapReduce, HDFS), matplotlib, pandas, NumPy, SciPy, Python essentials, AWS, and various command lines. python aws data-science machine-learn...
1 # quality code -0139 # dew point temperature (degrees Celsius x 10) 1 # quality code 10268 # atmospheric pressure (hectopascals x 10) 1 # quality code NOTE: 在一个文件中应该保存着多行这样的数据,我们可以看到这样一行数据中有气象站的代号、日期、时间、温度等重要信息。这一行信息的时间单位...
err.println("usage: Merge <in> <out>"); System.exit(2); } Job job = Job.getInstance(conf,"Merge"); job.setJarByClass(Merge.class); job.setMapperClass(Merge.Map.class); job.setReducerClass(Merge.Reduce.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(Text.class); ...