mirror of
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7c2bb5bc57
the itertoolsmodule. * Taught itertools.repeat(obj, n) to treat negative repeat counts as zero. This behavior matches that for sequences and prevents infinite loops.
328 lines
12 KiB
Python
328 lines
12 KiB
Python
import unittest
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from test import test_support
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from itertools import *
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import sys
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import operator
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def onearg(x):
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'Test function of one argument'
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return x
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def errfunc(*args):
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'Test function that raises an error'
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raise ValueError
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def gen3():
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'Non-restartable source sequence'
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for i in (0, 1, 2):
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yield i
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def isEven(x):
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'Test predicate'
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return x%2==0
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class StopNow:
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'Class emulating an empty iterable.'
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def __iter__(self):
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return self
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def next(self):
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raise StopIteration
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class TestBasicOps(unittest.TestCase):
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def test_chain(self):
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self.assertEqual(list(chain('abc', 'def')), list('abcdef'))
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self.assertEqual(list(chain('abc')), list('abc'))
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self.assertEqual(list(chain('')), [])
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self.assertRaises(TypeError, chain, 2, 3)
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def test_count(self):
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self.assertEqual(zip('abc',count()), [('a', 0), ('b', 1), ('c', 2)])
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self.assertEqual(zip('abc',count(3)), [('a', 3), ('b', 4), ('c', 5)])
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self.assertRaises(TypeError, count, 2, 3)
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self.assertRaises(TypeError, count, 'a')
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c = count(sys.maxint-2) # verify that rollover doesn't crash
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c.next(); c.next(); c.next(); c.next(); c.next()
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def test_cycle(self):
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self.assertEqual(list(islice(cycle('abc'),10)), list('abcabcabca'))
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self.assertEqual(list(cycle('')), [])
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self.assertRaises(TypeError, cycle)
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self.assertRaises(TypeError, cycle, 5)
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self.assertEqual(list(islice(cycle(gen3()),10)), [0,1,2,0,1,2,0,1,2,0])
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def test_ifilter(self):
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self.assertEqual(list(ifilter(isEven, range(6))), [0,2,4])
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self.assertEqual(list(ifilter(None, [0,1,0,2,0])), [1,2])
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self.assertRaises(TypeError, ifilter)
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self.assertRaises(TypeError, ifilter, lambda x:x)
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self.assertRaises(TypeError, ifilter, lambda x:x, range(6), 7)
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self.assertRaises(TypeError, ifilter, isEven, 3)
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self.assertRaises(TypeError, ifilter(range(6), range(6)).next)
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def test_ifilterfalse(self):
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self.assertEqual(list(ifilterfalse(isEven, range(6))), [1,3,5])
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self.assertEqual(list(ifilterfalse(None, [0,1,0,2,0])), [0,0,0])
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self.assertRaises(TypeError, ifilterfalse)
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self.assertRaises(TypeError, ifilterfalse, lambda x:x)
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self.assertRaises(TypeError, ifilterfalse, lambda x:x, range(6), 7)
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self.assertRaises(TypeError, ifilterfalse, isEven, 3)
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self.assertRaises(TypeError, ifilterfalse(range(6), range(6)).next)
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def test_izip(self):
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ans = [(x,y) for x, y in izip('abc',count())]
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self.assertEqual(ans, [('a', 0), ('b', 1), ('c', 2)])
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self.assertEqual(list(izip('abc', range(6))), zip('abc', range(6)))
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self.assertEqual(list(izip('abcdef', range(3))), zip('abcdef', range(3)))
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self.assertEqual(list(izip('abcdef')), zip('abcdef'))
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self.assertRaises(TypeError, izip)
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self.assertRaises(TypeError, izip, 3)
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self.assertRaises(TypeError, izip, range(3), 3)
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# Check tuple re-use (implementation detail)
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self.assertEqual([tuple(list(pair)) for pair in izip('abc', 'def')],
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zip('abc', 'def'))
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ids = map(id, izip('abc', 'def'))
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self.assertEqual(min(ids), max(ids))
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def test_repeat(self):
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self.assertEqual(zip(xrange(3),repeat('a')),
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[(0, 'a'), (1, 'a'), (2, 'a')])
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self.assertEqual(list(repeat('a', 3)), ['a', 'a', 'a'])
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self.assertEqual(list(repeat('a', 0)), [])
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self.assertEqual(list(repeat('a', -3)), [])
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self.assertRaises(TypeError, repeat)
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self.assertRaises(TypeError, repeat, None, 3, 4)
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self.assertRaises(TypeError, repeat, None, 'a')
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def test_imap(self):
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self.assertEqual(list(imap(operator.pow, range(3), range(1,7))),
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[0**1, 1**2, 2**3])
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self.assertEqual(list(imap(None, 'abc', range(5))),
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[('a',0),('b',1),('c',2)])
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self.assertEqual(list(imap(operator.pow, [])), [])
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self.assertRaises(TypeError, imap)
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self.assertRaises(TypeError, imap, operator.neg)
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self.assertRaises(TypeError, imap(10, range(5)).next)
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self.assertRaises(ValueError, imap(errfunc, [4], [5]).next)
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self.assertRaises(TypeError, imap(onearg, [4], [5]).next)
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def test_starmap(self):
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self.assertEqual(list(starmap(operator.pow, zip(range(3), range(1,7)))),
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[0**1, 1**2, 2**3])
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self.assertEqual(list(starmap(operator.pow, [])), [])
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self.assertRaises(TypeError, list, starmap(operator.pow, [[4,5]]))
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self.assertRaises(TypeError, starmap)
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self.assertRaises(TypeError, starmap, operator.pow, [(4,5)], 'extra')
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self.assertRaises(TypeError, starmap(10, [(4,5)]).next)
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self.assertRaises(ValueError, starmap(errfunc, [(4,5)]).next)
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self.assertRaises(TypeError, starmap(onearg, [(4,5)]).next)
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def test_islice(self):
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for args in [ # islice(args) should agree with range(args)
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(10, 20, 3),
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(10, 3, 20),
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(10, 20),
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(10, 3),
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(20,)
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]:
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self.assertEqual(list(islice(xrange(100), *args)), range(*args))
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for args, tgtargs in [ # Stop when seqn is exhausted
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((10, 110, 3), ((10, 100, 3))),
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((10, 110), ((10, 100))),
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((110,), (100,))
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]:
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self.assertEqual(list(islice(xrange(100), *args)), range(*tgtargs))
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# Test stop=None
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self.assertEqual(list(islice(xrange(10), None)), range(10))
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self.assertEqual(list(islice(xrange(10), 2, None)), range(2, 10))
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self.assertEqual(list(islice(xrange(10), 1, None, 2)), range(1, 10, 2))
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# Test invalid arguments
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self.assertRaises(TypeError, islice, xrange(10))
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self.assertRaises(TypeError, islice, xrange(10), 1, 2, 3, 4)
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self.assertRaises(ValueError, islice, xrange(10), -5, 10, 1)
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self.assertRaises(ValueError, islice, xrange(10), 1, -5, -1)
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self.assertRaises(ValueError, islice, xrange(10), 1, 10, -1)
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self.assertRaises(ValueError, islice, xrange(10), 1, 10, 0)
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self.assertRaises(ValueError, islice, xrange(10), 'a')
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self.assertRaises(ValueError, islice, xrange(10), 'a', 1)
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self.assertRaises(ValueError, islice, xrange(10), 1, 'a')
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self.assertRaises(ValueError, islice, xrange(10), 'a', 1, 1)
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self.assertRaises(ValueError, islice, xrange(10), 1, 'a', 1)
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self.assertEqual(len(list(islice(count(), 1, 10, sys.maxint))), 1)
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def test_takewhile(self):
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data = [1, 3, 5, 20, 2, 4, 6, 8]
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underten = lambda x: x<10
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self.assertEqual(list(takewhile(underten, data)), [1, 3, 5])
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self.assertEqual(list(takewhile(underten, [])), [])
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self.assertRaises(TypeError, takewhile)
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self.assertRaises(TypeError, takewhile, operator.pow)
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self.assertRaises(TypeError, takewhile, operator.pow, [(4,5)], 'extra')
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self.assertRaises(TypeError, takewhile(10, [(4,5)]).next)
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self.assertRaises(ValueError, takewhile(errfunc, [(4,5)]).next)
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def test_dropwhile(self):
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data = [1, 3, 5, 20, 2, 4, 6, 8]
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underten = lambda x: x<10
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self.assertEqual(list(dropwhile(underten, data)), [20, 2, 4, 6, 8])
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self.assertEqual(list(dropwhile(underten, [])), [])
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self.assertRaises(TypeError, dropwhile)
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self.assertRaises(TypeError, dropwhile, operator.pow)
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self.assertRaises(TypeError, dropwhile, operator.pow, [(4,5)], 'extra')
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self.assertRaises(TypeError, dropwhile(10, [(4,5)]).next)
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self.assertRaises(ValueError, dropwhile(errfunc, [(4,5)]).next)
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def test_StopIteration(self):
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for f in (chain, cycle, izip):
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self.assertRaises(StopIteration, f([]).next)
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self.assertRaises(StopIteration, f(StopNow()).next)
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self.assertRaises(StopIteration, islice([], None).next)
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self.assertRaises(StopIteration, islice(StopNow(), None).next)
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self.assertRaises(StopIteration, repeat(None, 0).next)
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for f in (ifilter, ifilterfalse, imap, takewhile, dropwhile, starmap):
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self.assertRaises(StopIteration, f(lambda x:x, []).next)
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self.assertRaises(StopIteration, f(lambda x:x, StopNow()).next)
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libreftest = """ Doctest for examples in the library reference, libitertools.tex
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>>> amounts = [120.15, 764.05, 823.14]
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>>> for checknum, amount in izip(count(1200), amounts):
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... print 'Check %d is for $%.2f' % (checknum, amount)
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...
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Check 1200 is for $120.15
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Check 1201 is for $764.05
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Check 1202 is for $823.14
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>>> import operator
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>>> import operator
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>>> for cube in imap(operator.pow, xrange(1,4), repeat(3)):
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... print cube
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...
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1
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8
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27
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>>> reportlines = ['EuroPython', 'Roster', '', 'alex', '', 'laura', '', 'martin', '', 'walter', '', 'samuele']
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>>> for name in islice(reportlines, 3, len(reportlines), 2):
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... print name.title()
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...
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Alex
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Laura
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Martin
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Walter
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Samuele
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>>> def enumerate(iterable):
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... return izip(count(), iterable)
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>>> def tabulate(function):
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... "Return function(0), function(1), ..."
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... return imap(function, count())
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>>> def iteritems(mapping):
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... return izip(mapping.iterkeys(), mapping.itervalues())
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>>> def nth(iterable, n):
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... "Returns the nth item"
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... return list(islice(iterable, n, n+1))
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>>> def all(pred, seq):
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... "Returns True if pred(x) is True for every element in the iterable"
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... return not nth(ifilterfalse(pred, seq), 0)
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>>> def some(pred, seq):
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... "Returns True if pred(x) is True at least one element in the iterable"
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... return bool(nth(ifilter(pred, seq), 0))
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>>> def no(pred, seq):
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... "Returns True if pred(x) is False for every element in the iterable"
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... return not nth(ifilter(pred, seq), 0)
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>>> def pairwise(seq):
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... "s -> (s0,s1), (s1,s2), (s2, s3), ..."
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... return izip(seq, islice(seq,1,len(seq)))
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>>> def padnone(seq):
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... "Returns the sequence elements and then returns None indefinitely"
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... return chain(seq, repeat(None))
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>>> def ncycles(seq, n):
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... "Returns the sequence elements n times"
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... return chain(*repeat(seq, n))
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>>> def dotproduct(vec1, vec2):
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... return sum(imap(operator.mul, vec1, vec2))
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This is not part of the examples but it tests to make sure the definitions
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perform as purported.
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>>> list(enumerate('abc'))
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[(0, 'a'), (1, 'b'), (2, 'c')]
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>>> list(islice(tabulate(lambda x: 2*x), 4))
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[0, 2, 4, 6]
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>>> nth('abcde', 3)
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['d']
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>>> all(lambda x: x%2==0, [2, 4, 6, 8])
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True
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>>> all(lambda x: x%2==0, [2, 3, 6, 8])
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False
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>>> some(lambda x: x%2==0, [2, 4, 6, 8])
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True
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>>> some(lambda x: x%2==0, [1, 3, 5, 9])
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False
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>>> no(lambda x: x%2==0, [1, 3, 5, 9])
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True
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>>> no(lambda x: x%2==0, [1, 2, 5, 9])
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False
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>>> list(pairwise('abc'))
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[('a', 'b'), ('b', 'c')]
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>>> list(islice(padnone('abc'), 0, 6))
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['a', 'b', 'c', None, None, None]
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>>> list(ncycles('abc', 3))
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['a', 'b', 'c', 'a', 'b', 'c', 'a', 'b', 'c']
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>>> dotproduct([1,2,3], [4,5,6])
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32
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"""
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__test__ = {'libreftest' : libreftest}
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def test_main(verbose=None):
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test_support.run_unittest(TestBasicOps)
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# verify reference counting
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import sys
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if verbose and hasattr(sys, "gettotalrefcount"):
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counts = [None] * 5
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for i in xrange(len(counts)):
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test_support.run_unittest(TestBasicOps)
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counts[i] = sys.gettotalrefcount()
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print counts
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# doctest the examples in the library reference
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import doctest
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doctest.testmod(sys.modules[__name__])
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if __name__ == "__main__":
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test_main(verbose=True)
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