Can some help me with writing a word count map reduce program in python?

Question

Programme must have a mapper class and a reducer class in addition to a driver class/method. Must be in python as i already know the same in Java.

Answer 1

The easiest way to do it through mrjob module, install it using pip.
Hese is a sample code for Map Reduce using mrjob module.

from mrjob.job import MRJob
from mrjob.step import MRStep

# Defining the Mappers and Reducers functions
# They should be defined inside the return of the steps function
# Here we have one Mapper and two Reducers
class planesCrashed(MRJob):
def steps(self):
return[
MRStep(mapper=self.mapper_get_year,
reducer=self.reducer_count_crash),
MRStep(reducer=self.reducer_count_crash_sort)
]

# Writing the body of the Mapper and return Key:Value pairs
def mapper_get_year(self,_,line):

b = line.split('\t')
(Date,Time,Location,Operator,Flight,Route,Type,Registration,cnIn,Aboard,Fatalities,Ground,Summary) = b

c = Date.split('/')
yield c[-1],1

# Writing the body of the first Reducer and return Key:Value pairs
def reducer_count_crash(self,key,values):
yield str(sum(values)).zfill(5),key

# Writing the body of the second Reducer and return Key:Value pairs
def reducer_count_crash_sort(self,count,years):
for year in years:
yield count,year

if __name__=='__main__':
planesCrashed.run()