Question

Update your mapper to remove punctuation marks during mapping.

mapper code below

#!/usr/bin/env python
#the above just indicates to use python to intepret this file
#This mapper code will input a line of text and output #

import sys
sys.path.append('.')

for line in sys.stdin:
   line = line.strip() #trim spaces from beginning and end
   keys = line.split() #split line by space
   for key in keys:
       value = 1
       print ("%s\t%d" % (key,value)) #for each word generate 'word TAB 1' line

Answer 1

#!/usr/bin/env python
#the above just indicates to use python to intepret this file
#This mapper code will input a line of text and output #

import sys

import string
sys.path.append('.')

for line in sys.stdin:
   line = line.strip() #trim spaces from beginning and end

line = line.strip(string.punctuation)

   keys = line.split() #split line by space
   for key in keys:
       value = 1
       print ("%s\t%d" % (key,value)) #for each word generate 'word TAB 1' line