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cpython/Lib/test/test_itertools.py
Guido van Rossum 47b9ff6ba1 Restructure comparison dramatically. There is no longer a default 
*ordering* between objects; there is only a default equality test
(defined by an object being equal to itself only).  Read the comment
in object.c.  The current implementation never uses a three-way
comparison to compute a rich comparison, but it does use a rich
comparison to compute a three-way comparison.  I'm not quite done
ripping out all the calls to PyObject_Compare/Cmp, or replacing
tp_compare implementations with tp_richcompare implementations;
but much of that has happened (to make most unit tests pass).

The following tests still fail, because I need help deciding
or understanding:

test_codeop -- depends on comparing code objects
test_datetime -- need Tim Peters' opinion
test_marshal -- depends on comparing code objects
test_mutants -- need help understanding it

The problem with test_codeop and test_marshal is this: these tests
compare two different code objects and expect them to be equal.
Is that still a feature we'd like to support?  I've temporarily
removed the comparison and hash code from code objects, so they
use the default (equality by pointer only) comparison.

For the other two tests, run them to see for yourself.
(There may be more failing test with "-u all".)

A general problem with getting lots of these tests to pass is
the reality that for object types that have a natural total ordering,
implementing __cmp__ is much more convenient than implementing
__eq__, __ne__, __lt__, and so on.  Should we go back to allowing
__cmp__ to provide a total ordering?  Should we provide some other
way to implement rich comparison with a single method override?
Alex proposed a __key__() method; I've considered a __richcmp__()
method.  Or perhaps __cmp__() just shouldn't be killed off...
2006-08-24 00:41:19 +00:00

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import unittest
from test import test_support
from itertools import *
from weakref import proxy
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()
c = count(3)
self.assertEqual(repr(c), 'count(3)')
c.next()
self.assertEqual(repr(c), 'count(4)')
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_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)
self.assertRaises(TypeError, groupby, 'abc', lambda x:x, 10)
# 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(sorted(s))]
self.assertEqual(r, ['a', 'b', 'c', 'd', 'r'])
# sort s | uniq -d
r = [k for k, g in groupby(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(sorted(s))]
self.assertEqual(r, [(5, 'a'), (2, 'b'), (1, 'c'), (1, 'd'), (2, 'r')])
# sort s | uniq -c | sort -rn | head -3
r = sorted([(len(list(g)) , k) for k, g in groupby(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 __eq__(self, dst):
raise ExpectedError
s = [DummyCmp(), DummyCmp(), None]
# __eq__ failure on outer object
self.assertRaises(ExpectedError, gulp, s, func=id)
# __eq__ 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])
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')
r = repeat(1+0j)
self.assertEqual(repr(r), 'repeat((1+0j))')
r = repeat(1+0j, 5)
self.assertEqual(repr(r), 'repeat((1+0j), 5)')
list(r)
self.assertEqual(repr(r), 'repeat((1+0j), 0)')
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), None, None)), range(10))
self.assertEqual(list(islice(xrange(10), None, None, 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 number of items consumed SF #1171417
it = iter(range(10))
self.assertEqual(list(islice(it, 3)), range(3))
self.assertEqual(list(it), range(3, 10))
# 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)
t = takewhile(bool, [1, 1, 1, 0, 0, 0])
self.assertEqual(list(t), [1, 1, 1])
self.assertRaises(StopIteration, t.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 = 200
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
for i in xrange(100):
self.assertEqual(a.next(), i)
del a
self.assertEqual(list(b), range(n))
a, b = tee(irange(n)) # test dealloc of trailing iterator
for i in xrange(100):
self.assertEqual(a.next(), i)
del b
self.assertEqual(list(a), range(100, 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))
# test argument format checking
self.assertRaises(TypeError, tee)
self.assertRaises(TypeError, tee, 3)
self.assertRaises(TypeError, tee, [1,2], 'x')
self.assertRaises(TypeError, tee, [1,2], 3, 'x')
# tee object should be instantiable
a, b = tee('abc')
c = type(a)('def')
self.assertEqual(list(c), list('def'))
# test long-lagged and multi-way split
a, b, c = tee(xrange(2000), 3)
for i in xrange(100):
self.assertEqual(a.next(), i)
self.assertEqual(list(b), range(2000))
self.assertEqual([c.next(), c.next()], range(2))
self.assertEqual(list(a), range(100,2000))
self.assertEqual(list(c), range(2,2000))
# test values of n
self.assertRaises(TypeError, tee, 'abc', 'invalid')
for n in xrange(5):
result = tee('abc', n)
self.assertEqual(type(result), tuple)
self.assertEqual(len(result), n)
self.assertEqual(map(list, result), [list('abc')]*n)
# tee pass-through to copyable iterator
a, b = tee('abc')
c, d = tee(a)
self.assert_(a is c)
# test tee_new
t1, t2 = tee('abc')
tnew = type(t1)
self.assertRaises(TypeError, tnew)
self.assertRaises(TypeError, tnew, 10)
t3 = tnew(t1)
self.assert_(list(t1) == list(t2) == list(t3) == list('abc'))
# test that tee objects are weak referencable
a, b = tee(xrange(10))
p = proxy(a)
self.assertEqual(getattr(p, '__class__'), type(b))
del a
self.assertRaises(ReferenceError, getattr, p, '__class__')
def test_StopIteration(self):
self.assertRaises(StopIteration, izip().next)
for f in (chain, cycle, izip, groupby):
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_dropwhile(self):
a = []
self.makecycle(dropwhile(bool, [0, a, a]), a)
def test_groupby(self):
a = []
self.makecycle(groupby([a]*2, lambda x:x), 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_repeat(self):
a = []
self.makecycle(repeat(a), a)
def test_starmap(self):
a = []
self.makecycle(starmap(lambda *t: t, [(a,a)]*2), a)
def test_takewhile(self):
a = []
self.makecycle(takewhile(bool, [1, 0, a, a]), a)
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, 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, cycle, N(s))
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, 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)):
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, 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, 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, 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, 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, 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, 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, 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, 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, tee, N(s))
self.assertRaises(ZeroDivisionError, list, tee(E(s))[0])
class LengthTransparency(unittest.TestCase):
def test_repeat(self):
from test.test_iterlen import len
self.assertEqual(len(repeat(None, 50)), 50)
self.assertRaises(TypeError, len, repeat(None))
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)
def test_sf_950057(self):
# Make sure that chain() and cycle() catch exceptions immediately
# rather than when shifting between input sources
def gen1():
hist.append(0)
yield 1
hist.append(1)
raise AssertionError
hist.append(2)
def gen2(x):
hist.append(3)
yield 2
hist.append(4)
if x:
raise StopIteration
hist = []
self.assertRaises(AssertionError, list, chain(gen1(), gen2(False)))
self.assertEqual(hist, [0,1])
hist = []
self.assertRaises(AssertionError, list, chain(gen1(), gen2(True)))
self.assertEqual(hist, [0,1])
hist = []
self.assertRaises(AssertionError, list, cycle(gen1()))
self.assertEqual(hist, [0,1])
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
>>> from operator import itemgetter
>>> d = dict(a=1, b=2, c=1, d=2, e=1, f=2, g=3)
>>> di = sorted(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']
# Find runs of consecutive numbers using groupby. The key to the solution
# is differencing with a range so that consecutive numbers all appear in
# same group.
>>> data = [ 1, 4,5,6, 10, 15,16,17,18, 22, 25,26,27,28]
>>> for k, g in groupby(enumerate(data), lambda (i,x):i-x):
... print map(operator.itemgetter(1), g)
...
[1]
[4, 5, 6]
[10]
[15, 16, 17, 18]
[22]
[25, 26, 27, 28]
>>> 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=None):
... "Returns True if pred(x) is true for every element in the iterable"
... for elem in ifilterfalse(pred, seq):
... return False
... return True
>>> def any(seq, pred=None):
... "Returns True if pred(x) is true for at least one element in the iterable"
... for elem in ifilter(pred, seq):
... return True
... return False
>>> def no(seq, pred=None):
... "Returns True if pred(x) is false for every element in the iterable"
... for elem in ifilter(pred, seq):
... return False
... return True
>>> def quantify(seq, pred=None):
... "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 pairwise(iterable):
... "s -> (s0,s1), (s1,s2), (s2, s3), ..."
... a, b = tee(iterable)
... try:
... b.next()
... except StopIteration:
... pass
... return izip(a, b)
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(pairwise('abcd'))
[('a', 'b'), ('b', 'c'), ('c', 'd')]
>>> list(pairwise([]))
[]
>>> list(pairwise('a'))
[]
>>> 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, LengthTransparency)
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)
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