[Python-checkins] python/dist/src/Lib/test test_itertools.py, 1.25, 1.26

[rhettinger at users.sourceforge.net]

Update of /cvsroot/python/python/dist/src/Lib/test
In directory sc8-pr-cvs1:/tmp/cvs-serv31126/Lib/test

Modified Files:
	test_itertools.py 
Log Message:
Implement itertools.groupby()

Original idea by Guido van Rossum.
Idea for skipable inner iterators by Raymond Hettinger.
Idea for argument order and identity function default by Alex Martelli.
Implementation by Hye-Shik Chang (with tweaks by Raymond Hettinger).



Index: test_itertools.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_itertools.py,v
retrieving revision 1.25
retrieving revision 1.26
diff -C2 -d -r1.25 -r1.26
*** test_itertools.py	12 Nov 2003 14:32:25 -0000	1.25
--- test_itertools.py	6 Dec 2003 16:23:06 -0000	1.26
***************
*** 62,65 ****
--- 62,153 ----
          self.assertEqual(list(islice(cycle(gen3()),10)), [0,1,2,0,1,2,0,1,2,0])
  
+     def test_groupby(self):
+         # Check whether it accepts arguments correctly
+         self.assertEqual([], list(groupby([])))
+         self.assertEqual([], list(groupby([], key=id)))
+         self.assertRaises(TypeError, list, groupby('abc', []))
+         self.assertRaises(TypeError, groupby, None)
+ 
+         # Check normal input
+         s = [(0, 10, 20), (0, 11,21), (0,12,21), (1,13,21), (1,14,22),
+              (2,15,22), (3,16,23), (3,17,23)]
+         dup = []
+         for k, g in groupby(s, lambda r:r[0]):
+             for elem in g:
+                 self.assertEqual(k, elem[0])
+                 dup.append(elem)
+         self.assertEqual(s, dup)
+ 
+         # Check nested case
+         dup = []
+         for k, g in groupby(s, lambda r:r[0]):
+             for ik, ig in groupby(g, lambda r:r[2]):
+                 for elem in ig:
+                     self.assertEqual(k, elem[0])
+                     self.assertEqual(ik, elem[2])
+                     dup.append(elem)
+         self.assertEqual(s, dup)
+ 
+         # Check case where inner iterator is not used
+         keys = [k for k, g in groupby(s, lambda r:r[0])]
+         expectedkeys = set([r[0] for r in s])
+         self.assertEqual(set(keys), expectedkeys)
+         self.assertEqual(len(keys), len(expectedkeys))
+ 
+         # Exercise pipes and filters style
+         s = 'abracadabra'
+         # sort s | uniq
+         r = [k for k, g in groupby(list.sorted(s))]
+         self.assertEqual(r, ['a', 'b', 'c', 'd', 'r'])
+         # sort s | uniq -d
+         r = [k for k, g in groupby(list.sorted(s)) if list(islice(g,1,2))]
+         self.assertEqual(r, ['a', 'b', 'r'])
+         # sort s | uniq -c
+         r = [(len(list(g)), k) for k, g in groupby(list.sorted(s))]
+         self.assertEqual(r, [(5, 'a'), (2, 'b'), (1, 'c'), (1, 'd'), (2, 'r')])
+         # sort s | uniq -c | sort -rn | head -3
+         r = list.sorted([(len(list(g)) , k) for k, g in groupby(list.sorted(s))], reverse=True)[:3]
+         self.assertEqual(r, [(5, 'a'), (2, 'r'), (2, 'b')])
+ 
+         # iter.next failure
+         class ExpectedError(Exception):
+             pass
+         def delayed_raise(n=0):
+             for i in range(n):
+                 yield 'yo'
+             raise ExpectedError
+         def gulp(iterable, keyp=None, func=list):
+             return [func(g) for k, g in groupby(iterable, keyp)]
+ 
+         # iter.next failure on outer object
+         self.assertRaises(ExpectedError, gulp, delayed_raise(0))
+         # iter.next failure on inner object
+         self.assertRaises(ExpectedError, gulp, delayed_raise(1))
+ 
+         # __cmp__ failure
+         class DummyCmp:
+             def __cmp__(self, dst):
+                 raise ExpectedError
+         s = [DummyCmp(), DummyCmp(), None]
+ 
+         # __cmp__ failure on outer object
+         self.assertRaises(ExpectedError, gulp, s, func=id)
+         # __cmp__ failure on inner object
+         self.assertRaises(ExpectedError, gulp, s)
+ 
+         # keyfunc failure
+         def keyfunc(obj):
+             if keyfunc.skip > 0:
+                 keyfunc.skip -= 1
+                 return obj
+             else:
+                 raise ExpectedError
+ 
+         # keyfunc failure on outer object
+         keyfunc.skip = 0
+         self.assertRaises(ExpectedError, gulp, [None], keyfunc)
+         keyfunc.skip = 1
+         self.assertRaises(ExpectedError, gulp, [None, None], keyfunc)
+ 
      def test_ifilter(self):
          self.assertEqual(list(ifilter(isEven, range(6))), [0,2,4])
***************
*** 269,273 ****
          self.assertRaises(StopIteration, izip().next)
  
!         for f in (chain, cycle, izip):
              self.assertRaises(StopIteration, f([]).next)
              self.assertRaises(StopIteration, f(StopNow()).next)
--- 357,361 ----
          self.assertRaises(StopIteration, izip().next)
  
!         for f in (chain, cycle, izip, groupby):
              self.assertRaises(StopIteration, f([]).next)
              self.assertRaises(StopIteration, f(StopNow()).next)
***************
*** 427,430 ****
--- 515,526 ----
              self.assertRaises(ZeroDivisionError, list, cycle(E(s)))
  
+     def test_groupby(self):
+         for s in (range(10), range(0), range(1000), (7,11), xrange(2000,2200,5)):
+             for g in (G, I, Ig, S, L, R):
+                 self.assertEqual([k for k, sb in groupby(g(s))], list(g(s)))
+             self.assertRaises(TypeError, groupby, X(s))
+             self.assertRaises(TypeError, list, groupby(N(s)))
+             self.assertRaises(ZeroDivisionError, list, groupby(E(s)))
+ 
      def test_ifilter(self):
          for s in (range(10), range(0), range(1000), (7,11), xrange(2000,2200,5)):
***************
*** 571,574 ****
--- 667,680 ----
  Walter
  Samuele
+ 
+ >>> from operator import itemgetter
+ >>> d = dict(a=1, b=2, c=1, d=2, e=1, f=2, g=3)
+ >>> di = list.sorted(d.iteritems(), key=itemgetter(1))
+ >>> for k, g in groupby(di, itemgetter(1)):
+ ...     print k, map(itemgetter(0), g)
+ ...
+ 1 ['a', 'c', 'e']
+ 2 ['b', 'd', 'f']
+ 3 ['g']
  
  >>> def take(n, seq):