Added sum_mapreduce.py

SimpleAddition/sum_mapreduce.py

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+'''
+This program uses Map reduce techniques to get sum of numers.
+How it works:
+We first call the mapper.py that prints the relevent data to the terminal.
+
+Then the reducer is called that prints out the sum of the numbers.
+This is just a very basic example that will not be of much use.
+But if you have gigabytes of numbers ot add , you cna run it with hadoop streaming.
+'''
+#!/usr/bin/env python
+
+import sys
+
+def mapper():
+	# Read input line
+	for line in sys.stdin:
+		# Strip off whitespace , and split on tab
+		data = line.strip().split('\t')
+
+		# We'll use the data stored in data/mapreduce/
+		# Having six columns of tab seperated values
+		# We'll make sure that correct data in sent through
+		print data
+		if len(data) ==2:
+			sr , num = data
+
+			# Now we'll print our data as required for the reducer task
+			# I need category and cost so we'll print that
+			print "{0}".format(num)
+
+mapper()
+
+'''
+
+# Testing :
+
+test_data = """1  54
+2 64
+3 1
+"""
+
+def main():
+
+	# Used for testing the mapper function
+
+	import StringIO
+	sys.stdin = StringIO.StringIO(test_data)
+	mapper()
+	sys.stdin = sys.__stdin__
+
+'''
+
+def reducer():
+	# Following the mapper.py , we need to get total
+	# sum.
+	Total = 0 
+
+	for line in sys.stdin:
+
+		data = line.strip().split("\t")
+
+		# Our mapper gives out 2 values
+
+		if len(data) != 1:
+			# This keeps check of the data errors
+			continue
+
+		thisnum = data 
+		Total += float(thisnum)
+
+	print Total
+
+
+# Calling the reducer function
+
+#reducer()