MapReduce Programming

8 / 13
   

MapReduce Programming - Find anagrams in a text file

Problem

Write a MapReduce code to find anagrams in a text file stored in HDFS. An anagram is basically a different arrangement of letters in a word. Anagram does not need to be meaningful

Dataset

The file is located at

/data/mr/wordcount/big.txt

Sample Output

Output file will contain the anagrams in the text file

3   ['bowel,', 'elbow,', 'below,']
3   ['bore', 'boer', 'robe']
3   ['bears', 'baser', 'saber']

Steps

  1. Check out the mapper.py and reducer.py in GitHub

  2. If you haven't cloned the CloudxLab GitHub repository, then clone it in your home folder in web console using the below command

    git clone https://github.com/singhabhinav/cloudxlab.git ~/cloudxlab
    
  3. Else, update the local copy

    cd ~/cloudxlab
    git pull origin master
    
  4. Go to find_anagrams directory

    cd ~/cloudxlab/hdpexamples/python-streaming/find_anagrams
    
  5. Run the MapReduce code using Hadoop streaming. Please make sure to save output in find_anagrams in mapreduce-programming/find_anagrams directory inside your home directory in HDFS. Run the below command

    hadoop jar /usr/hdp/2.3.4.0-3485/hadoop-mapreduce/hadoop-streaming.jar -input /data/mr/wordcount/big.txt -output mapreduce-programming/find_anagrams -mapper mapper.py -file mapper.py -reducer reducer.py -file reducer.py
    
  6. Check the frequency of characters by typing below command.

    hadoop fs -cat mapreduce-programming/find_anagrams/* | sort -nr | head -n 20