Merge pull request alteryx#46 from mateiz/py-sort-update

Fix PySpark docs and an overly long line of code after alteryx#38

Just noticed these after merging that commit (https://github.com/apache/incubator-spark/pull/38).

docs/python-programming-guide.md

@@ -16,7 +16,7 @@ This guide will show how to use the Spark features described there in Python.
 There are a few key differences between the Python and Scala APIs:
 
 * Python is dynamically typed, so RDDs can hold objects of multiple types.
-* PySpark does not yet support a few API calls, such as `lookup`, `sort`, and non-text input files, though these will be added in future releases.
+* PySpark does not yet support a few API calls, such as `lookup` and non-text input files, though these will be added in future releases.
 
 In PySpark, RDDs support the same methods as their Scala counterparts but take Python functions and return Python collection types.
 Short functions can be passed to RDD methods using Python's [`lambda`](http://www.diveintopython.net/power_of_introspection/lambda_functions.html) syntax:

python/pyspark/rdd.py

@@ -117,8 +117,6 @@ def getCheckpointFile(self):
         else:
             return None
 
-    # TODO persist(self, storageLevel)
-
     def map(self, f, preservesPartitioning=False):
         """
         Return a new RDD containing the distinct elements in this RDD.
@@ -227,7 +225,7 @@ def takeSample(self, withReplacement, num, seed):
             total = num
 
         samples = self.sample(withReplacement, fraction, seed).collect()
-    
+
         # If the first sample didn't turn out large enough, keep trying to take samples;
         # this shouldn't happen often because we use a big multiplier for their initial size.
         # See: scala/spark/RDD.scala
@@ -288,7 +286,7 @@ def sortByKey(self, ascending=True, numPartitions=None, keyfunc = lambda x: x):
             maxSampleSize = numPartitions * 20.0 # constant from Spark's RangePartitioner
             fraction = min(maxSampleSize / max(rddSize, 1), 1.0)
 
-            samples = self.sample(False, fraction, 1).map(lambda (k, v): k).collect()        
+            samples = self.sample(False, fraction, 1).map(lambda (k, v): k).collect()
             samples = sorted(samples, reverse=(not ascending), key=keyfunc)
 
             # we have numPartitions many parts but one of the them has
@@ -309,7 +307,9 @@ def rangePartitionFunc(k):
         def mapFunc(iterator):
             yield sorted(iterator, reverse=(not ascending), key=lambda (k, v): keyfunc(k))
 
-        return self.partitionBy(numPartitions, partitionFunc=rangePartitionFunc).mapPartitions(mapFunc,preservesPartitioning=True).flatMap(lambda x: x, preservesPartitioning=True)
+        return (self.partitionBy(numPartitions, partitionFunc=rangePartitionFunc)
+                    .mapPartitions(mapFunc,preservesPartitioning=True)
+                    .flatMap(lambda x: x, preservesPartitioning=True))
 
     def glom(self):
         """
@@ -471,7 +471,7 @@ def count(self):
         3
         """
         return self.mapPartitions(lambda i: [sum(1 for _ in i)]).sum()
-    
+
     def stats(self):
         """
         Return a L{StatCounter} object that captures the mean, variance
@@ -508,7 +508,7 @@ def stdev(self):
         0.816...
         """
         return self.stats().stdev()
-  
+
     def sampleStdev(self):
         """
         Compute the sample standard deviation of this RDD's elements (which corrects for bias in
@@ -878,7 +878,7 @@ def subtractByKey(self, other, numPartitions=None):
         >>> y = sc.parallelize([("a", 3), ("c", None)])
         >>> sorted(x.subtractByKey(y).collect())
         [('b', 4), ('b', 5)]
-        """ 
+        """
         filter_func = lambda (key, vals): len(vals[0]) > 0 and len(vals[1]) == 0
         map_func = lambda (key, vals): [(key, val) for val in vals[0]]
         return self.cogroup(other, numPartitions).filter(filter_func).flatMap(map_func)