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Promote compress() from a recipe to being a regular itertool.

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This commit is contained in:
Raymond Hettinger 2009-01-25 21:04:14 +00:00
parent 1af3b5a9a4
commit 2bcb8e9b0d
5 changed files with 206 additions and 13 deletions
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40
Lib/test/test_itertools.py
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@ -191,6 +191,21 @@ 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_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(''))
self.assertEqual(list(compress('ABCDEF', [1,1,1,1,1,1])), list('ABCDEF'))
self.assertEqual(list(compress('ABCDEF', [1,0,1])), list('AC'))
self.assertEqual(list(compress('ABC', [0,1,1,1,1,1])), list('BC'))
n = 10000
data = chain.from_iterable(repeat(range(6), n))
selectors = chain.from_iterable(repeat((0, 1)))
self.assertEqual(list(compress(data, selectors)), [1,3,5] * n)
self.assertRaises(TypeError, compress, None, range(6)) # 1st arg not iterable
self.assertRaises(TypeError, compress, range(6), None) # 2nd arg not iterable
self.assertRaises(TypeError, compress, range(6)) # too few args
self.assertRaises(TypeError, compress, range(6), None) # too many args
def test_count(self):
self.assertEqual(zip('abc',count()), [('a', 0), ('b', 1), ('c', 2)])
self.assertEqual(zip('abc',count(3)), [('a', 3), ('b', 4), ('c', 5)])
@ -701,6 +716,9 @@ class TestExamples(unittest.TestCase):
self.assertEqual(list(combinations(range(4), 3)),
[(0,1,2), (0,1,3), (0,2,3), (1,2,3)])
def test_compress(self):
self.assertEqual(list(compress('ABCDEF', [1,0,1,0,1,1])), list('ACEF'))
def test_count(self):
self.assertEqual(list(islice(count(10), 5)), [10, 11, 12, 13, 14])
@ -781,6 +799,10 @@ class TestGC(unittest.TestCase):
a = []
self.makecycle(combinations([1,2,a,3], 3), a)
def test_compress(self):
a = []
self.makecycle(compress('ABCDEF', [1,0,1,0,1,0]), a)
def test_cycle(self):
a = []
self.makecycle(cycle([a]*2), a)
@ -934,6 +956,15 @@ class TestVariousIteratorArgs(unittest.TestCase):
self.assertRaises(TypeError, list, chain(N(s)))
self.assertRaises(ZeroDivisionError, list, chain(E(s)))
def test_compress(self):
for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)):
n = len(s)
for g in (G, I, Ig, S, L, R):
self.assertEqual(list(compress(g(s), repeat(1))), list(g(s)))
self.assertRaises(TypeError, compress, X(s), repeat(1))
self.assertRaises(TypeError, list, compress(N(s), repeat(1)))
self.assertRaises(ZeroDivisionError, list, compress(E(s), repeat(1)))
def test_product(self):
for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)):
self.assertRaises(TypeError, product, X(s))
@ -1125,7 +1156,7 @@ class SubclassWithKwargsTest(unittest.TestCase):
def test_keywords_in_subclass(self):
# count is not subclassable...
for cls in (repeat, izip, ifilter, ifilterfalse, chain, imap,
starmap, islice, takewhile, dropwhile, cycle):
starmap, islice, takewhile, dropwhile, cycle, compress):
class Subclass(cls):
def __init__(self, newarg=None, *args):
cls.__init__(self, *args)
@ -1262,10 +1293,6 @@ Samuele
... for n in xrange(2**len(pairs)):
... yield set(x for m, x in pairs if m&n)
>>> def compress(data, selectors):
... "compress('ABCDEF', [1,0,1,0,1,1]) --> A C E F"
... return (d for d, s in izip(data, selectors) if s)
>>> def combinations_with_replacement(iterable, r):
... "combinations_with_replacement('ABC', 3) --> AA AB AC BB BC CC"
... pool = tuple(iterable)
@ -1361,9 +1388,6 @@ perform as purported.
>>> map(sorted, powerset('ab'))
[[], ['a'], ['b'], ['a', 'b']]
>>> list(compress('abcdef', [1,0,1,0,1,1]))
['a', 'c', 'e', 'f']
>>> list(combinations_with_replacement('abc', 2))
[('a', 'a'), ('a', 'b'), ('a', 'c'), ('b', 'b'), ('b', 'c'), ('c', 'c')]