Added keys and values methods for PairFunctions in python

Author: ScrapCodes

python/pyspark/rdd.py

@@ -690,6 +690,26 @@ def collectAsMap(self):
         """
         return dict(self.collect())
 
+    def keys(self):
+        """
+        Return an RDD with the keys of each tuple.
+        >>> m = sc.parallelize([(1, 2), (3, 4)]).keys()
+        >>> m.collect()
+        [1, 3]
+        """
+        map_only_keys_fn = lambda (k, v): k
+        return self.map(map_only_keys_fn)
+
+    def values(self):
+        """
+        Return an RDD with the values of each tuple.
+        >>> m = sc.parallelize([(1, 2), (3, 4)]).values()
+        >>> m.collect()
+        [2, 4]
+        """
+        map_only_values_fn = lambda (k, v): v
+        return self.map(map_only_values_fn)
+
     def reduceByKey(self, func, numPartitions=None):
         """
         Merge the values for each key using an associative reduce function.