add partition

TODO

@@ -8,7 +8,6 @@ itertoolz:
     get
     mapcat
     sliding_window
-    partition
     partition_all
     pluck
 

coolz/__init__.pxd

@@ -2,7 +2,7 @@ from .itertoolz cimport (groupby, frequencies, reduceby,
                          first, second, nth, take, drop, rest, last,
                          concat, concatv, isdistinct, interpose, unique,
                          isiterable, remove, iterate, accumulate,
-                         count, cons, take_nth)
+                         count, cons, take_nth, partition)
 
 from .functoolz cimport (memoize, c_memoize, curry, c_compose, c_thread_first,
                          c_thread_last, identity, c_pipe, complement, c_juxt,

coolz/__init__.py

@@ -2,7 +2,7 @@
                         first, second, nth, take, drop, rest, last,
                         concat, concatv, isdistinct, interpose, unique,
                         isiterable, remove, iterate, accumulate,
-                        count, cons, take_nth)
+                        count, cons, take_nth, partition)
 
 from .functoolz import (memoize, curry, compose, thread_first,
                         thread_last, identity, pipe, complement, juxt, do)

coolz/itertoolz/__init__.pxd

@@ -1,4 +1,4 @@
 from .core cimport (groupby, remove, concat, concatv, frequencies, interpose,
                     first, second, nth, take, drop, rest, last, unique,
                     reduceby, isiterable, isdistinct, cons, iterate,
-                    accumulate, count, take_nth)
+                    accumulate, count, take_nth, partition)

coolz/itertoolz/__init__.py

@@ -1,4 +1,4 @@
 from .core import (groupby, remove, concat, concatv, frequencies, interpose,
                    first, second, nth, take, drop, rest, last, unique,
                    reduceby, isiterable, isdistinct, cons, iterate,
-                   accumulate, count, take_nth)
+                   accumulate, count, take_nth, partition)

coolz/itertoolz/core.pxd

@@ -79,3 +79,6 @@ cdef class iterate:
 
 
 cpdef int count(object seq)
+
+
+cpdef object partition(int n, object seq, object pad=*)

coolz/itertoolz/core.pyx

@@ -3,7 +3,7 @@ from cpython.list cimport PyList_New, PyList_Append
 from cpython.ref cimport PyObject
 from cpython.sequence cimport PySequence_Check
 from cpython.set cimport PySet_Add, PySet_Contains
-from itertools import chain, islice
+from itertools import chain, islice, izip_longest
 
 
 concatv = chain
@@ -516,3 +516,31 @@ cpdef int count(object seq):
     for _ in seq:
         i += 1
     return i
+
+
+no_pad = '__no__pad__'
+
+
+cpdef object partition(int n, object seq, object pad=no_pad):
+    """ Partition sequence into tuples of length n
+
+    >>> list(partition(2, [1, 2, 3, 4]))
+    [(1, 2), (3, 4)]
+
+    If the length of ``seq`` is not evenly divisible by ``n``, the final tuple
+    is dropped if ``pad`` is not specified, or filled to length ``n`` by pad:
+
+    >>> list(partition(2, [1, 2, 3, 4, 5]))
+    [(1, 2), (3, 4)]
+
+    >>> list(partition(2, [1, 2, 3, 4, 5], pad=None))
+    [(1, 2), (3, 4), (5, None)]
+
+    See Also:
+        partition_all
+    """
+    args = [iter(seq)] * n
+    if pad is no_pad:
+        return zip(*args)
+    else:
+        return izip_longest(*args, fillvalue=pad)

coolz/itertoolz/tests/test_core.py

@@ -8,7 +8,7 @@
                                   nth, take, drop, interpose,
                                   rest, last, cons, frequencies,
                                   reduceby, iterate, accumulate,
-                                  count,
+                                  count, partition,
                                   take_nth)
 
 from toolz.compatibility import range, filter
@@ -236,16 +236,12 @@ def test_sliding_window_of_short_iterator():
     assert list(sliding_window(3, [1, 2])) == []
 '''
 
-
-'''
 def test_partition():
     assert list(partition(2, [1, 2, 3, 4])) == [(1, 2), (3, 4)]
     assert list(partition(3, range(7))) == [(0, 1, 2), (3, 4, 5)]
     assert list(partition(3, range(4), pad=-1)) == [(0, 1, 2),
                                                     (3, -1, -1)]
     assert list(partition(2, [])) == []
-'''
-
 
 '''
 def test_partition_all():