[SPARK-4897] [PySpark] Python 3 support

This PR update PySpark to support Python 3 (tested with 3.4).

Known issue: unpickle array from Pyrolite is broken in Python 3, those tests are skipped.

TODO: ec2/spark-ec2.py is not fully tested with python3.

Author: Davies Liu <davies@databricks.com>
Author: twneale <twneale@gmail.com>
Author: Josh Rosen <joshrosen@databricks.com>

Closes #5173 from davies/python3 and squashes the following commits:

d7d6323 [Davies Liu] fix tests
6c52a98 [Davies Liu] fix mllib test
99e334f [Davies Liu] update timeout
b716610 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
cafd5ec [Davies Liu] adddress comments from @mengxr
bf225d7 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
179fc8d [Davies Liu] tuning flaky tests
8c8b957 [Davies Liu] fix ResourceWarning in Python 3
5c57c95 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
4006829 [Davies Liu] fix test
2fc0066 [Davies Liu] add python3 path
71535e9 [Davies Liu] fix xrange and divide
5a55ab4 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
125f12c [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
ed498c8 [Davies Liu] fix compatibility with python 3
820e649 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
e8ce8c9 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
ad7c374 [Davies Liu] fix mllib test and warning
ef1fc2f [Davies Liu] fix tests
4eee14a [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
20112ff [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
59bb492 [Davies Liu] fix tests
1da268c [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
ca0fdd3 [Davies Liu] fix code style
9563a15 [Davies Liu] add imap back for python 2
0b1ec04 [Davies Liu] make python examples work with Python 3
d2fd566 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
a716d34 [Davies Liu] test with python 3.4
f1700e8 [Davies Liu] fix test in python3
671b1db [Davies Liu] fix test in python3
692ff47 [Davies Liu] fix flaky test
7b9699f [Davies Liu] invalidate import cache for Python 3.3+
9c58497 [Davies Liu] fix kill worker
309bfbf [Davies Liu] keep compatibility
5707476 [Davies Liu] cleanup, fix hash of string in 3.3+
8662d5b [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
f53e1f0 [Davies Liu] fix tests
70b6b73 [Davies Liu] compile ec2/spark_ec2.py in python 3
a39167e [Davies Liu] support customize class in __main__
814c77b [Davies Liu] run unittests with python 3
7f4476e [Davies Liu] mllib tests passed
d737924 [Davies Liu] pass ml tests
375ea17 [Davies Liu] SQL tests pass
6cc42a9 [Davies Liu] rename
431a8de [Davies Liu] streaming tests pass
78901a7 [Davies Liu] fix hash of serializer in Python 3
24b2f2e [Davies Liu] pass all RDD tests
35f48fe [Davies Liu] run future again
1eebac2 [Davies Liu] fix conflict in ec2/spark_ec2.py
6e3c21d [Davies Liu] make cloudpickle work with Python3
2fb2db3 [Josh Rosen] Guard more changes behind sys.version; still doesn't run
1aa5e8f [twneale] Turned out `pickle.DictionaryType is dict` == True, so swapped it out
7354371 [twneale] buffer --> memoryview  I'm not super sure if this a valid change, but the 2.7 docs recommend using memoryview over buffer where possible, so hoping it'll work.
b69ccdf [twneale] Uses the pure python pickle._Pickler instead of c-extension _pickle.Pickler. It appears pyspark 2.7 uses the pure python pickler as well, so this shouldn't degrade pickling performance (?).
f40d925 [twneale] xrange --> range
e104215 [twneale] Replaces 2.7 types.InstsanceType with 3.4 `object`....could be horribly wrong depending on how types.InstanceType is used elsewhere in the package--see http://bugs.python.org/issue8206
79de9d0 [twneale] Replaces python2.7 `file` with 3.4 _io.TextIOWrapper
2adb42d [Josh Rosen] Fix up some import differences between Python 2 and 3
854be27 [Josh Rosen] Run `futurize` on Python code:
7c5b4ce [Josh Rosen] Remove Python 3 check in shell.py.

1 files changed, 13 insertions, 12 deletions

diff --git a/python/pyspark/mllib/stat/_statistics.py b/python/pyspark/mllib/stat/_statistics.py
index 1d83e9d483..b475be4b4d 100644
--- a/python/pyspark/mllib/stat/_statistics.py
+++ b/python/pyspark/mllib/stat/_statistics.py
@@ -15,7 +15,7 @@
 # limitations under the License.
 #
 
-from pyspark import RDD
+from pyspark.rdd import RDD, ignore_unicode_prefix
 from pyspark.mllib.common import callMLlibFunc, JavaModelWrapper
 from pyspark.mllib.linalg import Matrix, _convert_to_vector
 from pyspark.mllib.regression import LabeledPoint
@@ -38,7 +38,7 @@ class MultivariateStatisticalSummary(JavaModelWrapper):
         return self.call("variance").toArray()
 
     def count(self):
-        return self.call("count")
+        return int(self.call("count"))
 
     def numNonzeros(self):
         return self.call("numNonzeros").toArray()
@@ -78,7 +78,7 @@ class Statistics(object):
         >>> cStats.variance()
         array([  4.,  13.,   0.,  25.])
         >>> cStats.count()
-        3L
+        3
         >>> cStats.numNonzeros()
         array([ 3.,  2.,  0.,  3.])
         >>> cStats.max()
@@ -124,20 +124,20 @@ class Statistics(object):
         >>> rdd = sc.parallelize([Vectors.dense([1, 0, 0, -2]), Vectors.dense([4, 5, 0, 3]),
         ...                       Vectors.dense([6, 7, 0,  8]), Vectors.dense([9, 0, 0, 1])])
         >>> pearsonCorr = Statistics.corr(rdd)
-        >>> print str(pearsonCorr).replace('nan', 'NaN')
+        >>> print(str(pearsonCorr).replace('nan', 'NaN'))
         [[ 1.          0.05564149         NaN  0.40047142]
          [ 0.05564149  1.                 NaN  0.91359586]
          [        NaN         NaN  1.                 NaN]
          [ 0.40047142  0.91359586         NaN  1.        ]]
         >>> spearmanCorr = Statistics.corr(rdd, method="spearman")
-        >>> print str(spearmanCorr).replace('nan', 'NaN')
+        >>> print(str(spearmanCorr).replace('nan', 'NaN'))
         [[ 1.          0.10540926         NaN  0.4       ]
          [ 0.10540926  1.                 NaN  0.9486833 ]
          [        NaN         NaN  1.                 NaN]
          [ 0.4         0.9486833          NaN  1.        ]]
         >>> try:
         ...     Statistics.corr(rdd, "spearman")
-        ...     print "Method name as second argument without 'method=' shouldn't be allowed."
+        ...     print("Method name as second argument without 'method=' shouldn't be allowed.")
         ... except TypeError:
         ...     pass
         """
@@ -153,6 +153,7 @@ class Statistics(object):
             return callMLlibFunc("corr", x.map(float), y.map(float), method)
 
     @staticmethod
+    @ignore_unicode_prefix
     def chiSqTest(observed, expected=None):
         """
         .. note:: Experimental
@@ -188,11 +189,11 @@ class Statistics(object):
         >>> from pyspark.mllib.linalg import Vectors, Matrices
         >>> observed = Vectors.dense([4, 6, 5])
         >>> pearson = Statistics.chiSqTest(observed)
-        >>> print pearson.statistic
+        >>> print(pearson.statistic)
         0.4
         >>> pearson.degreesOfFreedom
         2
-        >>> print round(pearson.pValue, 4)
+        >>> print(round(pearson.pValue, 4))
         0.8187
         >>> pearson.method
         u'pearson'
@@ -202,12 +203,12 @@ class Statistics(object):
         >>> observed = Vectors.dense([21, 38, 43, 80])
         >>> expected = Vectors.dense([3, 5, 7, 20])
         >>> pearson = Statistics.chiSqTest(observed, expected)
-        >>> print round(pearson.pValue, 4)
+        >>> print(round(pearson.pValue, 4))
         0.0027
 
         >>> data = [40.0, 24.0, 29.0, 56.0, 32.0, 42.0, 31.0, 10.0, 0.0, 30.0, 15.0, 12.0]
         >>> chi = Statistics.chiSqTest(Matrices.dense(3, 4, data))
-        >>> print round(chi.statistic, 4)
+        >>> print(round(chi.statistic, 4))
         21.9958
 
         >>> data = [LabeledPoint(0.0, Vectors.dense([0.5, 10.0])),
@@ -218,9 +219,9 @@ class Statistics(object):
         ...         LabeledPoint(1.0, Vectors.dense([3.5, 40.0])),]
         >>> rdd = sc.parallelize(data, 4)
         >>> chi = Statistics.chiSqTest(rdd)
-        >>> print chi[0].statistic
+        >>> print(chi[0].statistic)
         0.75
-        >>> print chi[1].statistic
+        >>> print(chi[1].statistic)
         1.5
         """
         if isinstance(observed, RDD):