| import unittest |
| from test import test_support |
| from itertools import * |
| import sys |
| import operator |
| import random |
| |
| def onearg(x): |
| 'Test function of one argument' |
| return 2*x |
| |
| def errfunc(*args): |
| 'Test function that raises an error' |
| raise ValueError |
| |
| def gen3(): |
| 'Non-restartable source sequence' |
| for i in (0, 1, 2): |
| yield i |
| |
| def isEven(x): |
| 'Test predicate' |
| return x%2==0 |
| |
| def isOdd(x): |
| 'Test predicate' |
| return x%2==1 |
| |
| class StopNow: |
| 'Class emulating an empty iterable.' |
| def __iter__(self): |
| return self |
| def next(self): |
| raise StopIteration |
| |
| def take(n, seq): |
| 'Convenience function for partially consuming a long of infinite iterable' |
| return list(islice(seq, n)) |
| |
| class TestBasicOps(unittest.TestCase): |
| def test_chain(self): |
| self.assertEqual(list(chain('abc', 'def')), list('abcdef')) |
| self.assertEqual(list(chain('abc')), list('abc')) |
| self.assertEqual(list(chain('')), []) |
| self.assertEqual(take(4, chain('abc', 'def')), list('abcd')) |
| self.assertRaises(TypeError, chain, 2, 3) |
| |
| 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)]) |
| self.assertEqual(take(2, zip('abc',count(3))), [('a', 3), ('b', 4)]) |
| self.assertRaises(TypeError, count, 2, 3) |
| self.assertRaises(TypeError, count, 'a') |
| c = count(sys.maxint-2) # verify that rollover doesn't crash |
| c.next(); c.next(); c.next(); c.next(); c.next() |
| |
| def test_cycle(self): |
| self.assertEqual(take(10, cycle('abc')), list('abcabcabca')) |
| self.assertEqual(list(cycle('')), []) |
| self.assertRaises(TypeError, cycle) |
| self.assertRaises(TypeError, cycle, 5) |
| self.assertEqual(list(islice(cycle(gen3()),10)), [0,1,2,0,1,2,0,1,2,0]) |
| |
| def test_ifilter(self): |
| self.assertEqual(list(ifilter(isEven, range(6))), [0,2,4]) |
| self.assertEqual(list(ifilter(None, [0,1,0,2,0])), [1,2]) |
| self.assertEqual(take(4, ifilter(isEven, count())), [0,2,4,6]) |
| self.assertRaises(TypeError, ifilter) |
| self.assertRaises(TypeError, ifilter, lambda x:x) |
| self.assertRaises(TypeError, ifilter, lambda x:x, range(6), 7) |
| self.assertRaises(TypeError, ifilter, isEven, 3) |
| self.assertRaises(TypeError, ifilter(range(6), range(6)).next) |
| |
| def test_ifilterfalse(self): |
| self.assertEqual(list(ifilterfalse(isEven, range(6))), [1,3,5]) |
| self.assertEqual(list(ifilterfalse(None, [0,1,0,2,0])), [0,0,0]) |
| self.assertEqual(take(4, ifilterfalse(isEven, count())), [1,3,5,7]) |
| self.assertRaises(TypeError, ifilterfalse) |
| self.assertRaises(TypeError, ifilterfalse, lambda x:x) |
| self.assertRaises(TypeError, ifilterfalse, lambda x:x, range(6), 7) |
| self.assertRaises(TypeError, ifilterfalse, isEven, 3) |
| self.assertRaises(TypeError, ifilterfalse(range(6), range(6)).next) |
| |
| def test_izip(self): |
| ans = [(x,y) for x, y in izip('abc',count())] |
| self.assertEqual(ans, [('a', 0), ('b', 1), ('c', 2)]) |
| self.assertEqual(list(izip('abc', range(6))), zip('abc', range(6))) |
| self.assertEqual(list(izip('abcdef', range(3))), zip('abcdef', range(3))) |
| self.assertEqual(take(3,izip('abcdef', count())), zip('abcdef', range(3))) |
| self.assertEqual(list(izip('abcdef')), zip('abcdef')) |
| self.assertEqual(list(izip()), zip()) |
| self.assertRaises(TypeError, izip, 3) |
| self.assertRaises(TypeError, izip, range(3), 3) |
| # Check tuple re-use (implementation detail) |
| self.assertEqual([tuple(list(pair)) for pair in izip('abc', 'def')], |
| zip('abc', 'def')) |
| self.assertEqual([pair for pair in izip('abc', 'def')], |
| zip('abc', 'def')) |
| ids = map(id, izip('abc', 'def')) |
| self.assertEqual(min(ids), max(ids)) |
| ids = map(id, list(izip('abc', 'def'))) |
| self.assertEqual(len(dict.fromkeys(ids)), len(ids)) |
| |
| def test_repeat(self): |
| self.assertEqual(zip(xrange(3),repeat('a')), |
| [(0, 'a'), (1, 'a'), (2, 'a')]) |
| self.assertEqual(list(repeat('a', 3)), ['a', 'a', 'a']) |
| self.assertEqual(take(3, repeat('a')), ['a', 'a', 'a']) |
| self.assertEqual(list(repeat('a', 0)), []) |
| self.assertEqual(list(repeat('a', -3)), []) |
| self.assertRaises(TypeError, repeat) |
| self.assertRaises(TypeError, repeat, None, 3, 4) |
| self.assertRaises(TypeError, repeat, None, 'a') |
| |
| def test_imap(self): |
| self.assertEqual(list(imap(operator.pow, range(3), range(1,7))), |
| [0**1, 1**2, 2**3]) |
| self.assertEqual(list(imap(None, 'abc', range(5))), |
| [('a',0),('b',1),('c',2)]) |
| self.assertEqual(list(imap(None, 'abc', count())), |
| [('a',0),('b',1),('c',2)]) |
| self.assertEqual(take(2,imap(None, 'abc', count())), |
| [('a',0),('b',1)]) |
| self.assertEqual(list(imap(operator.pow, [])), []) |
| self.assertRaises(TypeError, imap) |
| self.assertRaises(TypeError, imap, operator.neg) |
| self.assertRaises(TypeError, imap(10, range(5)).next) |
| self.assertRaises(ValueError, imap(errfunc, [4], [5]).next) |
| self.assertRaises(TypeError, imap(onearg, [4], [5]).next) |
| |
| def test_starmap(self): |
| self.assertEqual(list(starmap(operator.pow, zip(range(3), range(1,7)))), |
| [0**1, 1**2, 2**3]) |
| self.assertEqual(take(3, starmap(operator.pow, izip(count(), count(1)))), |
| [0**1, 1**2, 2**3]) |
| self.assertEqual(list(starmap(operator.pow, [])), []) |
| self.assertRaises(TypeError, list, starmap(operator.pow, [[4,5]])) |
| self.assertRaises(TypeError, starmap) |
| self.assertRaises(TypeError, starmap, operator.pow, [(4,5)], 'extra') |
| self.assertRaises(TypeError, starmap(10, [(4,5)]).next) |
| self.assertRaises(ValueError, starmap(errfunc, [(4,5)]).next) |
| self.assertRaises(TypeError, starmap(onearg, [(4,5)]).next) |
| |
| def test_islice(self): |
| for args in [ # islice(args) should agree with range(args) |
| (10, 20, 3), |
| (10, 3, 20), |
| (10, 20), |
| (10, 3), |
| (20,) |
| ]: |
| self.assertEqual(list(islice(xrange(100), *args)), range(*args)) |
| |
| for args, tgtargs in [ # Stop when seqn is exhausted |
| ((10, 110, 3), ((10, 100, 3))), |
| ((10, 110), ((10, 100))), |
| ((110,), (100,)) |
| ]: |
| self.assertEqual(list(islice(xrange(100), *args)), range(*tgtargs)) |
| |
| # Test stop=None |
| self.assertEqual(list(islice(xrange(10), None)), range(10)) |
| self.assertEqual(list(islice(xrange(10), 2, None)), range(2, 10)) |
| self.assertEqual(list(islice(xrange(10), 1, None, 2)), range(1, 10, 2)) |
| |
| # Test invalid arguments |
| self.assertRaises(TypeError, islice, xrange(10)) |
| self.assertRaises(TypeError, islice, xrange(10), 1, 2, 3, 4) |
| self.assertRaises(ValueError, islice, xrange(10), -5, 10, 1) |
| self.assertRaises(ValueError, islice, xrange(10), 1, -5, -1) |
| self.assertRaises(ValueError, islice, xrange(10), 1, 10, -1) |
| self.assertRaises(ValueError, islice, xrange(10), 1, 10, 0) |
| self.assertRaises(ValueError, islice, xrange(10), 'a') |
| self.assertRaises(ValueError, islice, xrange(10), 'a', 1) |
| self.assertRaises(ValueError, islice, xrange(10), 1, 'a') |
| self.assertRaises(ValueError, islice, xrange(10), 'a', 1, 1) |
| self.assertRaises(ValueError, islice, xrange(10), 1, 'a', 1) |
| self.assertEqual(len(list(islice(count(), 1, 10, sys.maxint))), 1) |
| |
| def test_takewhile(self): |
| data = [1, 3, 5, 20, 2, 4, 6, 8] |
| underten = lambda x: x<10 |
| self.assertEqual(list(takewhile(underten, data)), [1, 3, 5]) |
| self.assertEqual(list(takewhile(underten, [])), []) |
| self.assertRaises(TypeError, takewhile) |
| self.assertRaises(TypeError, takewhile, operator.pow) |
| self.assertRaises(TypeError, takewhile, operator.pow, [(4,5)], 'extra') |
| self.assertRaises(TypeError, takewhile(10, [(4,5)]).next) |
| self.assertRaises(ValueError, takewhile(errfunc, [(4,5)]).next) |
| |
| def test_dropwhile(self): |
| data = [1, 3, 5, 20, 2, 4, 6, 8] |
| underten = lambda x: x<10 |
| self.assertEqual(list(dropwhile(underten, data)), [20, 2, 4, 6, 8]) |
| self.assertEqual(list(dropwhile(underten, [])), []) |
| self.assertRaises(TypeError, dropwhile) |
| self.assertRaises(TypeError, dropwhile, operator.pow) |
| self.assertRaises(TypeError, dropwhile, operator.pow, [(4,5)], 'extra') |
| self.assertRaises(TypeError, dropwhile(10, [(4,5)]).next) |
| self.assertRaises(ValueError, dropwhile(errfunc, [(4,5)]).next) |
| |
| def test_tee(self): |
| n = 100 |
| def irange(n): |
| for i in xrange(n): |
| yield i |
| |
| a, b = tee([]) # test empty iterator |
| self.assertEqual(list(a), []) |
| self.assertEqual(list(b), []) |
| |
| a, b = tee(irange(n)) # test 100% interleaved |
| self.assertEqual(zip(a,b), zip(range(n),range(n))) |
| |
| a, b = tee(irange(n)) # test 0% interleaved |
| self.assertEqual(list(a), range(n)) |
| self.assertEqual(list(b), range(n)) |
| |
| a, b = tee(irange(n)) # test dealloc of leading iterator |
| self.assertEqual(a.next(), 0) |
| self.assertEqual(a.next(), 1) |
| del a |
| self.assertEqual(list(b), range(n)) |
| |
| a, b = tee(irange(n)) # test dealloc of trailing iterator |
| self.assertEqual(a.next(), 0) |
| self.assertEqual(a.next(), 1) |
| del b |
| self.assertEqual(list(a), range(2, n)) |
| |
| for j in xrange(5): # test randomly interleaved |
| order = [0]*n + [1]*n |
| random.shuffle(order) |
| lists = ([], []) |
| its = tee(irange(n)) |
| for i in order: |
| value = its[i].next() |
| lists[i].append(value) |
| self.assertEqual(lists[0], range(n)) |
| self.assertEqual(lists[1], range(n)) |
| |
| self.assertRaises(TypeError, tee) |
| self.assertRaises(TypeError, tee, 3) |
| self.assertRaises(TypeError, tee, [1,2], 'x') |
| |
| def test_StopIteration(self): |
| self.assertRaises(StopIteration, izip().next) |
| |
| for f in (chain, cycle, izip): |
| self.assertRaises(StopIteration, f([]).next) |
| self.assertRaises(StopIteration, f(StopNow()).next) |
| |
| self.assertRaises(StopIteration, islice([], None).next) |
| self.assertRaises(StopIteration, islice(StopNow(), None).next) |
| |
| p, q = tee([]) |
| self.assertRaises(StopIteration, p.next) |
| self.assertRaises(StopIteration, q.next) |
| p, q = tee(StopNow()) |
| self.assertRaises(StopIteration, p.next) |
| self.assertRaises(StopIteration, q.next) |
| |
| self.assertRaises(StopIteration, repeat(None, 0).next) |
| |
| for f in (ifilter, ifilterfalse, imap, takewhile, dropwhile, starmap): |
| self.assertRaises(StopIteration, f(lambda x:x, []).next) |
| self.assertRaises(StopIteration, f(lambda x:x, StopNow()).next) |
| |
| class TestGC(unittest.TestCase): |
| |
| def makecycle(self, iterator, container): |
| container.append(iterator) |
| iterator.next() |
| del container, iterator |
| |
| def test_chain(self): |
| a = [] |
| self.makecycle(chain(a), a) |
| |
| def test_cycle(self): |
| a = [] |
| self.makecycle(cycle([a]*2), a) |
| |
| def test_ifilter(self): |
| a = [] |
| self.makecycle(ifilter(lambda x:True, [a]*2), a) |
| |
| def test_ifilterfalse(self): |
| a = [] |
| self.makecycle(ifilterfalse(lambda x:False, a), a) |
| |
| def test_izip(self): |
| a = [] |
| self.makecycle(izip([a]*2, [a]*3), a) |
| |
| def test_imap(self): |
| a = [] |
| self.makecycle(imap(lambda x:x, [a]*2), a) |
| |
| def test_islice(self): |
| a = [] |
| self.makecycle(islice([a]*2, None), a) |
| |
| def test_starmap(self): |
| a = [] |
| self.makecycle(starmap(lambda *t: t, [(a,a)]*2), a) |
| |
| def test_tee(self): |
| a = [] |
| p, q = t = tee([a]*2) |
| a += [a, p, q, t] |
| p.next() |
| del a, p, q, t |
| |
| def R(seqn): |
| 'Regular generator' |
| for i in seqn: |
| yield i |
| |
| class G: |
| 'Sequence using __getitem__' |
| def __init__(self, seqn): |
| self.seqn = seqn |
| def __getitem__(self, i): |
| return self.seqn[i] |
| |
| class I: |
| 'Sequence using iterator protocol' |
| def __init__(self, seqn): |
| self.seqn = seqn |
| self.i = 0 |
| def __iter__(self): |
| return self |
| def next(self): |
| if self.i >= len(self.seqn): raise StopIteration |
| v = self.seqn[self.i] |
| self.i += 1 |
| return v |
| |
| class Ig: |
| 'Sequence using iterator protocol defined with a generator' |
| def __init__(self, seqn): |
| self.seqn = seqn |
| self.i = 0 |
| def __iter__(self): |
| for val in self.seqn: |
| yield val |
| |
| class X: |
| 'Missing __getitem__ and __iter__' |
| def __init__(self, seqn): |
| self.seqn = seqn |
| self.i = 0 |
| def next(self): |
| if self.i >= len(self.seqn): raise StopIteration |
| v = self.seqn[self.i] |
| self.i += 1 |
| return v |
| |
| class N: |
| 'Iterator missing next()' |
| def __init__(self, seqn): |
| self.seqn = seqn |
| self.i = 0 |
| def __iter__(self): |
| return self |
| |
| class E: |
| 'Test propagation of exceptions' |
| def __init__(self, seqn): |
| self.seqn = seqn |
| self.i = 0 |
| def __iter__(self): |
| return self |
| def next(self): |
| 3/0 |
| |
| class S: |
| 'Test immediate stop' |
| def __init__(self, seqn): |
| pass |
| def __iter__(self): |
| return self |
| def next(self): |
| raise StopIteration |
| |
| def L(seqn): |
| 'Test multiple tiers of iterators' |
| return chain(imap(lambda x:x, R(Ig(G(seqn))))) |
| |
| |
| class TestVariousIteratorArgs(unittest.TestCase): |
| |
| def test_chain(self): |
| for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)): |
| for g in (G, I, Ig, S, L, R): |
| self.assertEqual(list(chain(g(s))), list(g(s))) |
| self.assertEqual(list(chain(g(s), g(s))), list(g(s))+list(g(s))) |
| self.assertRaises(TypeError, chain, X(s)) |
| self.assertRaises(TypeError, list, chain(N(s))) |
| self.assertRaises(ZeroDivisionError, list, chain(E(s))) |
| |
| def test_cycle(self): |
| for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)): |
| for g in (G, I, Ig, S, L, R): |
| tgtlen = len(s) * 3 |
| expected = list(g(s))*3 |
| actual = list(islice(cycle(g(s)), tgtlen)) |
| self.assertEqual(actual, expected) |
| self.assertRaises(TypeError, cycle, X(s)) |
| self.assertRaises(TypeError, list, cycle(N(s))) |
| self.assertRaises(ZeroDivisionError, list, cycle(E(s))) |
| |
| def test_ifilter(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(list(ifilter(isEven, g(s))), filter(isEven, g(s))) |
| self.assertRaises(TypeError, ifilter, isEven, X(s)) |
| self.assertRaises(TypeError, list, ifilter(isEven, N(s))) |
| self.assertRaises(ZeroDivisionError, list, ifilter(isEven, E(s))) |
| |
| def test_ifilterfalse(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(list(ifilterfalse(isEven, g(s))), filter(isOdd, g(s))) |
| self.assertRaises(TypeError, ifilterfalse, isEven, X(s)) |
| self.assertRaises(TypeError, list, ifilterfalse(isEven, N(s))) |
| self.assertRaises(ZeroDivisionError, list, ifilterfalse(isEven, E(s))) |
| |
| def test_izip(self): |
| for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)): |
| for g in (G, I, Ig, S, L, R): |
| self.assertEqual(list(izip(g(s))), zip(g(s))) |
| self.assertEqual(list(izip(g(s), g(s))), zip(g(s), g(s))) |
| self.assertRaises(TypeError, izip, X(s)) |
| self.assertRaises(TypeError, list, izip(N(s))) |
| self.assertRaises(ZeroDivisionError, list, izip(E(s))) |
| |
| def test_imap(self): |
| for s in (range(10), range(0), range(100), (7,11), xrange(20,50,5)): |
| for g in (G, I, Ig, S, L, R): |
| self.assertEqual(list(imap(onearg, g(s))), map(onearg, g(s))) |
| self.assertEqual(list(imap(operator.pow, g(s), g(s))), map(operator.pow, g(s), g(s))) |
| self.assertRaises(TypeError, imap, onearg, X(s)) |
| self.assertRaises(TypeError, list, imap(onearg, N(s))) |
| self.assertRaises(ZeroDivisionError, list, imap(onearg, E(s))) |
| |
| def test_islice(self): |
| for s in ("12345", "", range(1000), ('do', 1.2), xrange(2000,2200,5)): |
| for g in (G, I, Ig, S, L, R): |
| self.assertEqual(list(islice(g(s),1,None,2)), list(g(s))[1::2]) |
| self.assertRaises(TypeError, islice, X(s), 10) |
| self.assertRaises(TypeError, list, islice(N(s), 10)) |
| self.assertRaises(ZeroDivisionError, list, islice(E(s), 10)) |
| |
| def test_starmap(self): |
| for s in (range(10), range(0), range(100), (7,11), xrange(20,50,5)): |
| for g in (G, I, Ig, S, L, R): |
| ss = zip(s, s) |
| self.assertEqual(list(starmap(operator.pow, g(ss))), map(operator.pow, g(s), g(s))) |
| self.assertRaises(TypeError, starmap, operator.pow, X(ss)) |
| self.assertRaises(TypeError, list, starmap(operator.pow, N(ss))) |
| self.assertRaises(ZeroDivisionError, list, starmap(operator.pow, E(ss))) |
| |
| def test_takewhile(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): |
| tgt = [] |
| for elem in g(s): |
| if not isEven(elem): break |
| tgt.append(elem) |
| self.assertEqual(list(takewhile(isEven, g(s))), tgt) |
| self.assertRaises(TypeError, takewhile, isEven, X(s)) |
| self.assertRaises(TypeError, list, takewhile(isEven, N(s))) |
| self.assertRaises(ZeroDivisionError, list, takewhile(isEven, E(s))) |
| |
| def test_dropwhile(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): |
| tgt = [] |
| for elem in g(s): |
| if not tgt and isOdd(elem): continue |
| tgt.append(elem) |
| self.assertEqual(list(dropwhile(isOdd, g(s))), tgt) |
| self.assertRaises(TypeError, dropwhile, isOdd, X(s)) |
| self.assertRaises(TypeError, list, dropwhile(isOdd, N(s))) |
| self.assertRaises(ZeroDivisionError, list, dropwhile(isOdd, E(s))) |
| |
| def test_tee(self): |
| for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)): |
| for g in (G, I, Ig, S, L, R): |
| it1, it2 = tee(g(s)) |
| self.assertEqual(list(it1), list(g(s))) |
| self.assertEqual(list(it2), list(g(s))) |
| self.assertRaises(TypeError, tee, X(s)) |
| self.assertRaises(TypeError, list, tee(N(s))[0]) |
| self.assertRaises(ZeroDivisionError, list, tee(E(s))[0]) |
| |
| class RegressionTests(unittest.TestCase): |
| |
| def test_sf_793826(self): |
| # Fix Armin Rigo's successful efforts to wreak havoc |
| |
| def mutatingtuple(tuple1, f, tuple2): |
| # this builds a tuple t which is a copy of tuple1, |
| # then calls f(t), then mutates t to be equal to tuple2 |
| # (needs len(tuple1) == len(tuple2)). |
| def g(value, first=[1]): |
| if first: |
| del first[:] |
| f(z.next()) |
| return value |
| items = list(tuple2) |
| items[1:1] = list(tuple1) |
| gen = imap(g, items) |
| z = izip(*[gen]*len(tuple1)) |
| z.next() |
| |
| def f(t): |
| global T |
| T = t |
| first[:] = list(T) |
| |
| first = [] |
| mutatingtuple((1,2,3), f, (4,5,6)) |
| second = list(T) |
| self.assertEqual(first, second) |
| |
| |
| libreftest = """ Doctest for examples in the library reference: libitertools.tex |
| |
| |
| >>> amounts = [120.15, 764.05, 823.14] |
| >>> for checknum, amount in izip(count(1200), amounts): |
| ... print 'Check %d is for $%.2f' % (checknum, amount) |
| ... |
| Check 1200 is for $120.15 |
| Check 1201 is for $764.05 |
| Check 1202 is for $823.14 |
| |
| >>> import operator |
| >>> for cube in imap(operator.pow, xrange(1,4), repeat(3)): |
| ... print cube |
| ... |
| 1 |
| 8 |
| 27 |
| |
| >>> reportlines = ['EuroPython', 'Roster', '', 'alex', '', 'laura', '', 'martin', '', 'walter', '', 'samuele'] |
| >>> for name in islice(reportlines, 3, None, 2): |
| ... print name.title() |
| ... |
| Alex |
| Laura |
| Martin |
| Walter |
| Samuele |
| |
| >>> def take(n, seq): |
| ... return list(islice(seq, n)) |
| |
| >>> def enumerate(iterable): |
| ... return izip(count(), iterable) |
| |
| >>> def tabulate(function): |
| ... "Return function(0), function(1), ..." |
| ... return imap(function, count()) |
| |
| >>> def iteritems(mapping): |
| ... return izip(mapping.iterkeys(), mapping.itervalues()) |
| |
| >>> def nth(iterable, n): |
| ... "Returns the nth item" |
| ... return list(islice(iterable, n, n+1)) |
| |
| >>> def all(seq, pred=bool): |
| ... "Returns True if pred(x) is True for every element in the iterable" |
| ... return False not in imap(pred, seq) |
| |
| >>> def any(seq, pred=bool): |
| ... "Returns True if pred(x) is True for at least one element in the iterable" |
| ... return True in imap(pred, seq) |
| |
| >>> def no(seq, pred=bool): |
| ... "Returns True if pred(x) is False for every element in the iterable" |
| ... return True not in imap(pred, seq) |
| |
| >>> def quantify(seq, pred=bool): |
| ... "Count how many times the predicate is True in the sequence" |
| ... return sum(imap(pred, seq)) |
| |
| >>> def padnone(seq): |
| ... "Returns the sequence elements and then returns None indefinitely" |
| ... return chain(seq, repeat(None)) |
| |
| >>> def ncycles(seq, n): |
| ... "Returns the sequence elements n times" |
| ... return chain(*repeat(seq, n)) |
| |
| >>> def dotproduct(vec1, vec2): |
| ... return sum(imap(operator.mul, vec1, vec2)) |
| |
| >>> def flatten(listOfLists): |
| ... return list(chain(*listOfLists)) |
| |
| >>> def repeatfunc(func, times=None, *args): |
| ... "Repeat calls to func with specified arguments." |
| ... " Example: repeatfunc(random.random)" |
| ... if times is None: |
| ... return starmap(func, repeat(args)) |
| ... else: |
| ... return starmap(func, repeat(args, times)) |
| |
| >>> def window(seq, n=2): |
| ... "Returns a sliding window (of width n) over data from the iterable" |
| ... " s -> (s0,s1,...s[n-1]), (s1,s2,...,sn), ... " |
| ... it = iter(seq) |
| ... result = tuple(islice(it, n)) |
| ... if len(result) == n: |
| ... yield result |
| ... for elem in it: |
| ... result = result[1:] + (elem,) |
| ... yield result |
| |
| This is not part of the examples but it tests to make sure the definitions |
| perform as purported. |
| |
| >>> take(10, count()) |
| [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] |
| |
| >>> list(enumerate('abc')) |
| [(0, 'a'), (1, 'b'), (2, 'c')] |
| |
| >>> list(islice(tabulate(lambda x: 2*x), 4)) |
| [0, 2, 4, 6] |
| |
| >>> nth('abcde', 3) |
| ['d'] |
| |
| >>> all([2, 4, 6, 8], lambda x: x%2==0) |
| True |
| |
| >>> all([2, 3, 6, 8], lambda x: x%2==0) |
| False |
| |
| >>> any([2, 4, 6, 8], lambda x: x%2==0) |
| True |
| |
| >>> any([1, 3, 5, 9], lambda x: x%2==0,) |
| False |
| |
| >>> no([1, 3, 5, 9], lambda x: x%2==0) |
| True |
| |
| >>> no([1, 2, 5, 9], lambda x: x%2==0) |
| False |
| |
| >>> quantify(xrange(99), lambda x: x%2==0) |
| 50 |
| |
| >>> a = [[1, 2, 3], [4, 5, 6]] |
| >>> flatten(a) |
| [1, 2, 3, 4, 5, 6] |
| |
| >>> list(repeatfunc(pow, 5, 2, 3)) |
| [8, 8, 8, 8, 8] |
| |
| >>> import random |
| >>> take(5, imap(int, repeatfunc(random.random))) |
| [0, 0, 0, 0, 0] |
| |
| >>> list(window('abc')) |
| [('a', 'b'), ('b', 'c')] |
| |
| >>> list(window('abc',5)) |
| [] |
| |
| >>> list(islice(padnone('abc'), 0, 6)) |
| ['a', 'b', 'c', None, None, None] |
| |
| >>> list(ncycles('abc', 3)) |
| ['a', 'b', 'c', 'a', 'b', 'c', 'a', 'b', 'c'] |
| |
| >>> dotproduct([1,2,3], [4,5,6]) |
| 32 |
| |
| """ |
| |
| __test__ = {'libreftest' : libreftest} |
| |
| def test_main(verbose=None): |
| test_classes = (TestBasicOps, TestVariousIteratorArgs, TestGC, |
| RegressionTests) |
| test_support.run_unittest(*test_classes) |
| |
| # verify reference counting |
| if verbose and hasattr(sys, "gettotalrefcount"): |
| import gc |
| counts = [None] * 5 |
| for i in xrange(len(counts)): |
| test_support.run_unittest(*test_classes) |
| gc.collect() |
| counts[i] = sys.gettotalrefcount() |
| print counts |
| |
| # doctest the examples in the library reference |
| test_support.run_doctest(sys.modules[__name__], verbose) |
| |
| if __name__ == "__main__": |
| test_main(verbose=True) |