Map Reduce Programs


A map/reduce program that counts the words in the input files.

Usage:bin/hadoop jar <path to jar file> wordcount <path of input file> <path of output directory>

Let us take the movies.txt file as input,which contains the following text data,

1,The Nightmare Before Christmas,1993,3.9,4568
2,The Mummy,1932,3.5,4388
3,Orphans of the Storm,1921,3.2,9062
4,The Object of Beauty,1991,2.8,6150
5,Night Tide,1963,2.8,5126
6,One Magic Christmas,1985,3.8,5333
7,Muriel’s Wedding,1994,3.5,6323
8,Mother’s Boys,1994,3.4,5733
9,Nosferatu: Original Version,1929,3.5,5651
10,Nick of Time,1995,3.4,5333

Then on executing the wordcount program we get the following output:

1,The 1
10,Nick 1
2,The 1
3,Orphans 1
4,The 1
5,Night 1
6,One 1
7,Muriel’s 1
8,Mother’s 1
9,Nosferatu: 1
Beauty,1991,2.8,6150 1
Before 1
Boys,1994,3.4,5733 1
Christmas,1985,3.8,5333 1
Christmas,1993,3.9,4568 1
Magic 1
Mummy,1932,3.5,4388 1
Nightmare 1
Object 1
Original 1
Storm,1921,3.2,9062 1
Tide,1963,2.8,5126 1
Time,1995,3.4,5333 1
Version,1929,3.5,5651 1
Wedding,1994,3.5,6323 1
of 3
the 1

Thus we can conclude that on executing the wordcount program we get the number of occurrence of a given word in a file.

<word> <no. of times it has occurred>


wc wcR


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