diff options
Diffstat (limited to 'Lib/test/test_itertools.py')
| -rw-r--r-- | Lib/test/test_itertools.py | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py index 7c858eb..affad7f 100644 --- a/Lib/test/test_itertools.py +++ b/Lib/test/test_itertools.py @@ -110,6 +110,14 @@ class TestBasicOps(unittest.TestCase): if sorted(indices) == list(indices): yield tuple(pool[i] for i in indices) + def combinations3(iterable, r): + 'Pure python version from cwr()' + pool = tuple(iterable) + n = len(pool) + for indices in combinations_with_replacement(range(n), r): + if len(set(indices)) == r: + yield tuple(pool[i] for i in indices) + for n in range(7): values = [5*x-12 for x in range(n)] for r in range(n+2): @@ -126,6 +134,7 @@ class TestBasicOps(unittest.TestCase): [e for e in values if e in c]) # comb is a subsequence of the input iterable self.assertEqual(result, list(combinations1(values, r))) # matches first pure python version self.assertEqual(result, list(combinations2(values, r))) # matches second pure python version + self.assertEqual(result, list(combinations3(values, r))) # matches second pure python version # Test implementation detail: tuple re-use self.assertEqual(len(set(map(id, combinations('abcde', 3)))), 1) @@ -265,6 +274,23 @@ class TestBasicOps(unittest.TestCase): self.assertEqual(len(set(map(id, permutations('abcde', 3)))), 1) self.assertNotEqual(len(set(map(id, list(permutations('abcde', 3))))), 1) + def test_combinatorics(self): + # Test relationships between product(), permutations(), + # combinations() and combinations_with_replacement(). + + s = 'ABCDE' + for r in range(8): + prod = list(product(s, repeat=r)) + cwr = list(combinations_with_replacement(s, r)) + perm = list(permutations(s, r)) + comb = list(combinations(s, r)) + + self.assertEquals(cwr, [t for t in prod if sorted(t)==list(t)]) # cwr: prods which are sorted + self.assertEquals(perm, [t for t in prod if len(set(t))==r]) # perm: prods with no dups + self.assertEqual(comb, [t for t in perm if sorted(t)==list(t)]) # comb: perms that are sorted + self.assertEqual(comb, [t for t in cwr if len(set(t))==r]) # comb: cwrs without dups + self.assertEqual(set(comb), set(cwr) & set(perm)) # comb: both a cwr and a perm + def test_compress(self): self.assertEqual(list(compress('ABCDEF', [1,0,1,0,1,1])), list('ACEF')) self.assertEqual(list(compress('ABCDEF', [0,0,0,0,0,0])), list('')) |