Added pairRdd/aggregation/combinebykey/AverageHousePriceSolution.py

Author: Pedro Bernardo

pairRdd/aggregation/combinebykey/AverageHousePriceSolution.py

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+from pyspark import SparkContext
+
+if __name__ == "__main__":
+
+    sc = SparkContext("local", "AverageHousePrice")
+    sc.setLogLevel("ERROR")
+
+    lines = sc.textFile("in/RealEstate.csv")
+    cleanedLines = lines.filter(lambda line: "Bedrooms" not in line)
+
+    housePricePairRdd = cleanedLines.map(lambda line: (line.split(",")[3], float(line.split(",")[2])))
+
+    createCombiner = lambda x: (1, x)
+    mergeValue = lambda avgCount, x: (avgCount[0] + 1, avgCount[1] + x)
+    mergeCombiners = lambda avgCountA, avgCountB: (avgCountA[0] + avgCountB[0], avgCountA[1] + avgCountB[1])
+
+    housePriceTotal = housePricePairRdd.combineByKey(createCombiner, mergeValue, mergeCombiners)
+
+    housePriceAvg = housePriceTotal.mapValues(lambda avgCount: avgCount[1] / avgCount[0])
+    for bedrooms, avgPrice in housePriceAvg.collect():
+        print("{} : {}".format(bedrooms, avgPrice))