import unittest from test import support from itertools import * from weakref import proxy from decimal import Decimal from fractions import Fraction import sys import operator import random import copy import pickle from functools import reduce import sys import struct maxsize = support.MAX_Py_ssize_t minsize = -maxsize-1 def lzip(*args): return list(zip(*args)) 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 def tupleize(*args): return args def irange(n): for i in range(n): yield i 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)) def prod(iterable): return reduce(operator.mul, iterable, 1) def fact(n): 'Factorial' return prod(range(1, n+1)) # root level methods for pickling ability def testR(r): return r[0] def testR2(r): return r[2] def underten(x): return x<10 class TestBasicOps(unittest.TestCase): def pickletest(self, it, stop=4, take=1, compare=None): """Test that an iterator is the same after pickling, also when part-consumed""" def expand(it, i=0): # Recursively expand iterables, within sensible bounds if i > 10: raise RuntimeError("infinite recursion encountered") if isinstance(it, str): return it try: l = list(islice(it, stop)) except TypeError: return it # can't expand it return [expand(e, i+1) for e in l] # Test the initial copy against the original dump = pickle.dumps(it) i2 = pickle.loads(dump) self.assertEqual(type(it), type(i2)) a, b = expand(it), expand(i2) self.assertEqual(a, b) if compare: c = expand(compare) self.assertEqual(a, c) # Take from the copy, and create another copy and compare them. i3 = pickle.loads(dump) took = 0 try: for i in range(take): next(i3) took += 1 except StopIteration: pass #in case there is less data than 'take' dump = pickle.dumps(i3) i4 = pickle.loads(dump) a, b = expand(i3), expand(i4) self.assertEqual(a, b) if compare: c = expand(compare[took:]) self.assertEqual(a, c); def test_accumulate(self): self.assertEqual(list(accumulate(range(10))), # one positional arg [0, 1, 3, 6, 10, 15, 21, 28, 36, 45]) self.assertEqual(list(accumulate(iterable=range(10))), # kw arg [0, 1, 3, 6, 10, 15, 21, 28, 36, 45]) for typ in int, complex, Decimal, Fraction: # multiple types self.assertEqual( list(accumulate(map(typ, range(10)))), list(map(typ, [0, 1, 3, 6, 10, 15, 21, 28, 36, 45]))) self.assertEqual(list(accumulate('abc')), ['a', 'ab', 'abc']) # works with non-numeric self.assertEqual(list(accumulate([])), []) # empty iterable self.assertEqual(list(accumulate([7])), [7]) # iterable of length one self.assertRaises(TypeError, accumulate, range(10), 5, 6) # too many args self.assertRaises(TypeError, accumulate) # too few args self.assertRaises(TypeError, accumulate, x=range(10)) # unexpected kwd arg self.assertRaises(TypeError, list, accumulate([1, []])) # args that don't add s = [2, 8, 9, 5, 7, 0, 3, 4, 1, 6] self.assertEqual(list(accumulate(s, min)), [2, 2, 2, 2, 2, 0, 0, 0, 0, 0]) self.assertEqual(list(accumulate(s, max)), [2, 8, 9, 9, 9, 9, 9, 9, 9, 9]) self.assertEqual(list(accumulate(s, operator.mul)), [2, 16, 144, 720, 5040, 0, 0, 0, 0, 0]) with self.assertRaises(TypeError): list(accumulate(s, chr)) # unary-operation self.pickletest(accumulate(range(10))) # test pickling def test_chain(self): def chain2(*iterables): 'Pure python version in the docs' for it in iterables: for element in it: yield element for c in (chain, chain2): self.assertEqual(list(c('abc', 'def')), list('abcdef')) self.assertEqual(list(c('abc')), list('abc')) self.assertEqual(list(c('')), []) self.assertEqual(take(4, c('abc', 'def')), list('abcd')) self.assertRaises(TypeError, list,c(2, 3)) def test_chain_from_iterable(self): self.assertEqual(list(chain.from_iterable(['abc', 'def'])), list('abcdef')) self.assertEqual(list(chain.from_iterable(['abc'])), list('abc')) self.assertEqual(list(chain.from_iterable([''])), []) self.assertEqual(take(4, chain.from_iterable(['abc', 'def'])), list('abcd')) self.assertRaises(TypeError, list, chain.from_iterable([2, 3])) def test_chain_reducible(self): operators = [copy.deepcopy, lambda s: pickle.loads(pickle.dumps(s))] for oper in operators: it = chain('abc', 'def') self.assertEqual(list(oper(it)), list('abcdef')) self.assertEqual(next(it), 'a') self.assertEqual(list(oper(it)), list('bcdef')) self.assertEqual(list(oper(chain(''))), []) self.assertEqual(take(4, oper(chain('abc', 'def'))), list('abcd')) self.assertRaises(TypeError, list, oper(chain(2, 3))) self.pickletest(chain('abc', 'def'), compare=list('abcdef')) def test_combinations(self): self.assertRaises(TypeError, combinations, 'abc') # missing r argument self.assertRaises(TypeError, combinations, 'abc', 2, 1) # too many arguments self.assertRaises(TypeError, combinations, None) # pool is not iterable self.assertRaises(ValueError, combinations, 'abc', -2) # r is negative for op in (lambda a:a, lambda a:pickle.loads(pickle.dumps(a))): self.assertEqual(list(op(combinations('abc', 32))), []) # r > n self.assertEqual(list(op(combinations('ABCD', 2))), [('A','B'), ('A','C'), ('A','D'), ('B','C'), ('B','D'), ('C','D')]) testIntermediate = combinations('ABCD', 2) next(testIntermediate) self.assertEqual(list(op(testIntermediate)), [('A','C'), ('A','D'), ('B','C'), ('B','D'), ('C','D')]) self.assertEqual(list(op(combinations(range(4), 3))), [(0,1,2), (0,1,3), (0,2,3), (1,2,3)]) testIntermediate = combinations(range(4), 3) next(testIntermediate) self.assertEqual(list(op(testIntermediate)), [(0,1,3), (0,2,3), (1,2,3)]) def combinations1(iterable, r): 'Pure python version shown in the docs' pool = tuple(iterable) n = len(pool) if r > n: return indices = list(range(r)) yield tuple(pool[i] for i in indices) while 1: for i in reversed(range(r)): if indices[i] != i + n - r: break else: return indices[i] += 1 for j in range(i+1, r): indices[j] = indices[j-1] + 1 yield tuple(pool[i] for i in indices) def combinations2(iterable, r): 'Pure python version shown in the docs' pool = tuple(iterable) n = len(pool) for indices in permutations(range(n), r): 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): result = list(combinations(values, r)) self.assertEqual(len(result), 0 if r>n else fact(n) / fact(r) / fact(n-r)) # right number of combs self.assertEqual(len(result), len(set(result))) # no repeats self.assertEqual(result, sorted(result)) # lexicographic order for c in result: self.assertEqual(len(c), r) # r-length combinations self.assertEqual(len(set(c)), r) # no duplicate elements self.assertEqual(list(c), sorted(c)) # keep original ordering self.assertTrue(all(e in values for e in c)) # elements taken from input iterable self.assertEqual(list(c), [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 self.pickletest(combinations(values, r)) # test pickling # Test implementation detail: tuple re-use @support.impl_detail("tuple reuse is specific to CPython") def test_combinations_tuple_reuse(self): self.assertEqual(len(set(map(id, combinations('abcde', 3)))), 1) self.assertNotEqual(len(set(map(id, list(combinations('abcde', 3))))), 1) def test_combinations_with_replacement(self): cwr = combinations_with_replacement self.assertRaises(TypeError, cwr, 'abc') # missing r argument self.assertRaises(TypeError, cwr, 'abc', 2, 1) # too many arguments self.assertRaises(TypeError, cwr, None) # pool is not iterable self.assertRaises(ValueError, cwr, 'abc', -2) # r is negative for op in (lambda a:a, lambda a:pickle.loads(pickle.dumps(a))): self.assertEqual(list(op(cwr('ABC', 2))), [('A','A'), ('A','B'), ('A','C'), ('B','B'), ('B','C'), ('C','C')]) testIntermediate = cwr('ABC', 2) next(testIntermediate) self.assertEqual(list(op(testIntermediate)), [('A','B'), ('A','C'), ('B','B'), ('B','C'), ('C','C')]) def cwr1(iterable, r): 'Pure python version shown in the docs' # number items returned: (n+r-1)! / r! / (n-1)! when n>0 pool = tuple(iterable) n = len(pool) if not n and r: return indices = [0] * r yield tuple(pool[i] for i in indices) while 1: for i in reversed(range(r)): if indices[i] != n - 1: break else: return indices[i:] = [indices[i] + 1] * (r - i) yield tuple(pool[i] for i in indices) def cwr2(iterable, r): 'Pure python version shown in the docs' pool = tuple(iterable) n = len(pool) for indices in product(range(n), repeat=r): if sorted(indices) == list(indices): yield tuple(pool[i] for i in indices) def numcombs(n, r): if not n: return 0 if r else 1 return fact(n+r-1) / fact(r)/ fact(n-1) for n in range(7): values = [5*x-12 for x in range(n)] for r in range(n+2): result = list(cwr(values, r)) self.assertEqual(len(result), numcombs(n, r)) # right number of combs self.assertEqual(len(result), len(set(result))) # no repeats self.assertEqual(result, sorted(result)) # lexicographic order regular_combs = list(combinations(values, r)) # compare to combs without replacement if n == 0 or r <= 1: self.assertEqual(result, regular_combs) # cases that should be identical else: self.assertTrue(set(result) >= set(regular_combs)) # rest should be supersets of regular combs for c in result: self.assertEqual(len(c), r) # r-length combinations noruns = [k for k,v in groupby(c)] # combo without consecutive repeats self.assertEqual(len(noruns), len(set(noruns))) # no repeats other than consecutive self.assertEqual(list(c), sorted(c)) # keep original ordering self.assertTrue(all(e in values for e in c)) # elements taken from input iterable self.assertEqual(noruns, [e for e in values if e in c]) # comb is a subsequence of the input iterable self.assertEqual(result, list(cwr1(values, r))) # matches first pure python version self.assertEqual(result, list(cwr2(values, r))) # matches second pure python version self.pickletest(cwr(values,r)) # test pickling # Test implementation detail: tuple re-use @support.impl_detail("tuple reuse is specific to CPython") def test_combinations_with_replacement_tuple_reuse(self): cwr = combinations_with_replacement self.assertEqual(len(set(map(id, cwr('abcde', 3)))), 1) self.assertNotEqual(len(set(map(id, list(cwr('abcde', 3))))), 1) def test_permutations(self): self.assertRaises(TypeError, permutations) # too few arguments self.assertRaises(TypeError, permutations, 'abc', 2, 1) # too many arguments self.assertRaises(TypeError, permutations, None) # pool is not iterable self.assertRaises(ValueError, permutations, 'abc', -2) # r is negative self.assertEqual(list(permutations('abc', 32)), []) # r > n self.assertRaises(TypeError, permutations, 'abc', 's') # r is not an int or None self.assertEqual(list(permutations(range(3), 2)), [(0,1), (0,2), (1,0), (1,2), (2,0), (2,1)]) def permutations1(iterable, r=None): 'Pure python version shown in the docs' pool = tuple(iterable) n = len(pool) r = n if r is None else r if r > n: return indices = list(range(n)) cycles = list(range(n-r+1, n+1))[::-1] yield tuple(pool[i] for i in indices[:r]) while n: for i in reversed(range(r)): cycles[i] -= 1 if cycles[i] == 0: indices[i:] = indices[i+1:] + indices[i:i+1] cycles[i] = n - i else: j = cycles[i] indices[i], indices[-j] = indices[-j], indices[i] yield tuple(pool[i] for i in indices[:r]) break else: return def permutations2(iterable, r=None): 'Pure python version shown in the docs' pool = tuple(iterable) n = len(pool) r = n if r is None else r for indices in product(range(n), repeat=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): result = list(permutations(values, r)) self.assertEqual(len(result), 0 if r>n else fact(n) / fact(n-r)) # right number of perms self.assertEqual(len(result), len(set(result))) # no repeats self.assertEqual(result, sorted(result)) # lexicographic order for p in result: self.assertEqual(len(p), r) # r-length permutations self.assertEqual(len(set(p)), r) # no duplicate elements self.assertTrue(all(e in values for e in p)) # elements taken from input iterable self.assertEqual(result, list(permutations1(values, r))) # matches first pure python version self.assertEqual(result, list(permutations2(values, r))) # matches second pure python version if r == n: self.assertEqual(result, list(permutations(values, None))) # test r as None self.assertEqual(result, list(permutations(values))) # test default r self.pickletest(permutations(values, r)) # test pickling @support.impl_detail("tuple resuse is CPython specific") def test_permutations_tuple_reuse(self): 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(). for n in range(6): s = 'ABCDEFG'[:n] 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)) # Check size self.assertEqual(len(prod), n**r) self.assertEqual(len(cwr), (fact(n+r-1) / fact(r)/ fact(n-1)) if n else (not r)) self.assertEqual(len(perm), 0 if r>n else fact(n) / fact(n-r)) self.assertEqual(len(comb), 0 if r>n else fact(n) / fact(r) / fact(n-r)) # Check lexicographic order without repeated tuples self.assertEqual(prod, sorted(set(prod))) self.assertEqual(cwr, sorted(set(cwr))) self.assertEqual(perm, sorted(set(perm))) self.assertEqual(comb, sorted(set(comb))) # Check interrelationships self.assertEqual(cwr, [t for t in prod if sorted(t)==list(t)]) # cwr: prods which are sorted self.assertEqual(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(comb, list(filter(set(cwr).__contains__, perm))) # comb: perm that is a cwr self.assertEqual(comb, list(filter(set(perm).__contains__, cwr))) # comb: cwr that is a perm self.assertEqual(comb, sorted(set(cwr) & set(perm))) # comb: both a cwr and a perm def test_compress(self): self.assertEqual(list(compress(data='ABCDEF', selectors=[1,0,1,0,1,1])), list('ACEF')) 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 # check copy, deepcopy, pickle for op in (lambda a:copy.copy(a), lambda a:copy.deepcopy(a), lambda a:pickle.loads(pickle.dumps(a))): for data, selectors, result1, result2 in [ ('ABCDEF', [1,0,1,0,1,1], 'ACEF', 'CEF'), ('ABCDEF', [0,0,0,0,0,0], '', ''), ('ABCDEF', [1,1,1,1,1,1], 'ABCDEF', 'BCDEF'), ('ABCDEF', [1,0,1], 'AC', 'C'), ('ABC', [0,1,1,1,1,1], 'BC', 'C'), ]: self.assertEqual(list(op(compress(data=data, selectors=selectors))), list(result1)) self.assertEqual(list(op(compress(data, selectors))), list(result1)) testIntermediate = compress(data, selectors) if result1: next(testIntermediate) self.assertEqual(list(op(testIntermediate)), list(result2)) def test_count(self): self.assertEqual(lzip('abc',count()), [('a', 0), ('b', 1), ('c', 2)]) self.assertEqual(lzip('abc',count(3)), [('a', 3), ('b', 4), ('c', 5)]) self.assertEqual(take(2, lzip('abc',count(3))), [('a', 3), ('b', 4)]) self.assertEqual(take(2, zip('abc',count(-1))), [('a', -1), ('b', 0)]) self.assertEqual(take(2, zip('abc',count(-3))), [('a', -3), ('b', -2)]) self.assertRaises(TypeError, count, 2, 3, 4) self.assertRaises(TypeError, count, 'a') self.assertEqual(list(islice(count(maxsize-5), 10)), list(range(maxsize-5, maxsize+5))) self.assertEqual(list(islice(count(-maxsize-5), 10)), list(range(-maxsize-5, -maxsize+5))) self.assertEqual(list(islice(count(10, maxsize+5), 3)), list(range(10, 10+3*(maxsize+5), maxsize+5))) c = count(3) self.assertEqual(repr(c), 'count(3)') next(c) self.assertEqual(repr(c), 'count(4)') c = count(-9) self.assertEqual(repr(c), 'count(-9)') next(c) self.assertEqual(repr(count(10.25)), 'count(10.25)') self.assertEqual(next(c), -8) for i in (-sys.maxsize-5, -sys.maxsize+5 ,-10, -1, 0, 10, sys.maxsize-5, sys.maxsize+5): # Test repr r1 = repr(count(i)) r2 = 'count(%r)'.__mod__(i) self.assertEqual(r1, r2) # check copy, deepcopy, pickle for value in -3, 3, maxsize-5, maxsize+5: c = count(value) self.assertEqual(next(copy.copy(c)), value) self.assertEqual(next(copy.deepcopy(c)), value) self.pickletest(count(value)) #check proper internal error handling for large "step' sizes count(1, maxsize+5); sys.exc_info() def test_count_with_stride(self): self.assertEqual(lzip('abc',count(2,3)), [('a', 2), ('b', 5), ('c', 8)]) self.assertEqual(lzip('abc',count(start=2,step=3)), [('a', 2), ('b', 5), ('c', 8)]) self.assertEqual(lzip('abc',count(step=-1)), [('a', 0), ('b', -1), ('c', -2)]) self.assertEqual(lzip('abc',count(2,0)), [('a', 2), ('b', 2), ('c', 2)]) self.assertEqual(lzip('abc',count(2,1)), [('a', 2), ('b', 3), ('c', 4)]) self.assertEqual(lzip('abc',count(2,3)), [('a', 2), ('b', 5), ('c', 8)]) self.assertEqual(take(20, count(maxsize-15, 3)), take(20, range(maxsize-15, maxsize+100, 3))) self.assertEqual(take(20, count(-maxsize-15, 3)), take(20, range(-maxsize-15,-maxsize+100, 3))) self.assertEqual(take(3, count(2, 3.25-4j)), [2, 5.25-4j, 8.5-8j]) self.assertEqual(take(3, count(Decimal('1.1'), Decimal('.1'))), [Decimal('1.1'), Decimal('1.2'), Decimal('1.3')]) self.assertEqual(take(3, count(Fraction(2,3), Fraction(1,7))), [Fraction(2,3), Fraction(17,21), Fraction(20,21)]) self.assertEqual(repr(take(3, count(10, 2.5))), repr([10, 12.5, 15.0])) c = count(3, 5) self.assertEqual(repr(c), 'count(3, 5)') next(c) self.assertEqual(repr(c), 'count(8, 5)') c = count(-9, 0) self.assertEqual(repr(c), 'count(-9, 0)') next(c) self.assertEqual(repr(c), 'count(-9, 0)') c = count(-9, -3) self.assertEqual(repr(c), 'count(-9, -3)') next(c) self.assertEqual(repr(c), 'count(-12, -3)') self.assertEqual(repr(c), 'count(-12, -3)') self.assertEqual(repr(count(10.5, 1.25)), 'count(10.5, 1.25)') self.assertEqual(repr(count(10.5, 1)), 'count(10.5)') # suppress step=1 when it's an int self.assertEqual(repr(count(10.5, 1.00)), 'count(10.5, 1.0)') # do show float values lilke 1.0 for i in (-sys.maxsize-5, -sys.maxsize+5 ,-10, -1, 0, 10, sys.maxsize-5, sys.maxsize+5): for j in (-sys.maxsize-5, -sys.maxsize+5 ,-10, -1, 0, 1, 10, sys.maxsize-5, sys.maxsize+5): # Test repr r1 = repr(count(i, j)) if j == 1: r2 = ('count(%r)' % i) else: r2 = ('count(%r, %r)' % (i, j)) self.assertEqual(r1, r2) self.pickletest(count(i, j)) 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]) # check copy, deepcopy, pickle c = cycle('abc') self.assertEqual(next(c), 'a') #simple copy currently not supported, because __reduce__ returns #an internal iterator #self.assertEqual(take(10, copy.copy(c)), list('bcabcabcab')) self.assertEqual(take(10, copy.deepcopy(c)), list('bcabcabcab')) self.assertEqual(take(10, pickle.loads(pickle.dumps(c))), list('bcabcabcab')) next(c) self.assertEqual(take(10, pickle.loads(pickle.dumps(c))), list('cabcabcabc')) self.pickletest(cycle('abc')) 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 normal pickled dup = [] for k, g in pickle.loads(pickle.dumps(groupby(s, testR))): 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, testR): for ik, ig in groupby(g, testR2): for elem in ig: self.assertEqual(k, elem[0]) self.assertEqual(ik, elem[2]) dup.append(elem) self.assertEqual(s, dup) # Check nested and pickled dup = [] for k, g in pickle.loads(pickle.dumps(groupby(s, testR))): for ik, ig in pickle.loads(pickle.dumps(groupby(g, testR2))): 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, testR)] 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_filter(self): self.assertEqual(list(filter(isEven, range(6))), [0,2,4]) self.assertEqual(list(filter(None, [0,1,0,2,0])), [1,2]) self.assertEqual(list(filter(bool, [0,1,0,2,0])), [1,2]) self.assertEqual(take(4, filter(isEven, count())), [0,2,4,6]) self.assertRaises(TypeError, filter) self.assertRaises(TypeError, filter, lambda x:x) self.assertRaises(TypeError, filter, lambda x:x, range(6), 7) self.assertRaises(TypeError, filter, isEven, 3) self.assertRaises(TypeError, next, filter(range(6), range(6))) # check copy, deepcopy, pickle ans = [0,2,4] c = filter(isEven, range(6)) self.assertEqual(list(copy.copy(c)), ans) c = filter(isEven, range(6)) self.assertEqual(list(copy.deepcopy(c)), ans) c = filter(isEven, range(6)) self.assertEqual(list(pickle.loads(pickle.dumps(c))), ans) next(c) self.assertEqual(list(pickle.loads(pickle.dumps(c))), ans[1:]) c = filter(isEven, range(6)) self.pickletest(c) def test_filterfalse(self): self.assertEqual(list(filterfalse(isEven, range(6))), [1,3,5]) self.assertEqual(list(filterfalse(None, [0,1,0,2,0])), [0,0,0]) self.assertEqual(list(filterfalse(bool, [0,1,0,2,0])), [0,0,0]) self.assertEqual(take(4, filterfalse(isEven, count())), [1,3,5,7]) self.assertRaises(TypeError, filterfalse) self.assertRaises(TypeError, filterfalse, lambda x:x) self.assertRaises(TypeError, filterfalse, lambda x:x, range(6), 7) self.assertRaises(TypeError, filterfalse, isEven, 3) self.assertRaises(TypeError, next, filterfalse(range(6), range(6))) self.pickletest(filterfalse(isEven, range(6))) def test_zip(self): # XXX This is rather silly now that builtin zip() calls zip()... ans = [(x,y) for x, y in zip('abc',count())] self.assertEqual(ans, [('a', 0), ('b', 1), ('c', 2)]) self.assertEqual(list(zip('abc', range(6))), lzip('abc', range(6))) self.assertEqual(list(zip('abcdef', range(3))), lzip('abcdef', range(3))) self.assertEqual(take(3,zip('abcdef', count())), lzip('abcdef', range(3))) self.assertEqual(list(zip('abcdef')), lzip('abcdef')) self.assertEqual(list(zip()), lzip()) self.assertRaises(TypeError, zip, 3) self.assertRaises(TypeError, zip, range(3), 3) self.assertEqual([tuple(list(pair)) for pair in zip('abc', 'def')], lzip('abc', 'def')) self.assertEqual([pair for pair in zip('abc', 'def')], lzip('abc', 'def')) @support.impl_detail("tuple reuse is specific to CPython") def test_zip_tuple_reuse(self): ids = list(map(id, zip('abc', 'def'))) self.assertEqual(min(ids), max(ids)) ids = list(map(id, list(zip('abc', 'def')))) self.assertEqual(len(dict.fromkeys(ids)), len(ids)) # check copy, deepcopy, pickle ans = [(x,y) for x, y in copy.copy(zip('abc',count()))] self.assertEqual(ans, [('a', 0), ('b', 1), ('c', 2)]) ans = [(x,y) for x, y in copy.deepcopy(zip('abc',count()))] self.assertEqual(ans, [('a', 0), ('b', 1), ('c', 2)]) ans = [(x,y) for x, y in pickle.loads(pickle.dumps(zip('abc',count())))] self.assertEqual(ans, [('a', 0), ('b', 1), ('c', 2)]) testIntermediate = zip('abc',count()) next(testIntermediate) ans = [(x,y) for x, y in pickle.loads(pickle.dumps(testIntermediate))] self.assertEqual(ans, [('b', 1), ('c', 2)]) self.pickletest(zip('abc', count())) def test_ziplongest(self): for args in [ ['abc', range(6)], [range(6), 'abc'], [range(1000), range(2000,2100), range(3000,3050)], [range(1000), range(0), range(3000,3050), range(1200), range(1500)], [range(1000), range(0), range(3000,3050), range(1200), range(1500), range(0)], ]: target = [tuple([arg[i] if i < len(arg) else None for arg in args]) for i in range(max(map(len, args)))] self.assertEqual(list(zip_longest(*args)), target) self.assertEqual(list(zip_longest(*args, **{})), target) target = [tuple((e is None and 'X' or e) for e in t) for t in target] # Replace None fills with 'X' self.assertEqual(list(zip_longest(*args, **dict(fillvalue='X'))), target) self.assertEqual(take(3,zip_longest('abcdef', count())), list(zip('abcdef', range(3)))) # take 3 from infinite input self.assertEqual(list(zip_longest()), list(zip())) self.assertEqual(list(zip_longest([])), list(zip([]))) self.assertEqual(list(zip_longest('abcdef')), list(zip('abcdef'))) self.assertEqual(list(zip_longest('abc', 'defg', **{})), list(zip(list('abc')+[None], 'defg'))) # empty keyword dict self.assertRaises(TypeError, zip_longest, 3) self.assertRaises(TypeError, zip_longest, range(3), 3) for stmt in [ "zip_longest('abc', fv=1)", "zip_longest('abc', fillvalue=1, bogus_keyword=None)", ]: try: eval(stmt, globals(), locals()) except TypeError: pass else: self.fail('Did not raise Type in: ' + stmt) self.assertEqual([tuple(list(pair)) for pair in zip_longest('abc', 'def')], list(zip('abc', 'def'))) self.assertEqual([pair for pair in zip_longest('abc', 'def')], list(zip('abc', 'def'))) @support.impl_detail("tuple reuse is specific to CPython") def test_zip_longest_tuple_reuse(self): ids = list(map(id, zip_longest('abc', 'def'))) self.assertEqual(min(ids), max(ids)) ids = list(map(id, list(zip_longest('abc', 'def')))) self.assertEqual(len(dict.fromkeys(ids)), len(ids)) def test_zip_longest_pickling(self): self.pickletest(zip_longest("abc", "def")) self.pickletest(zip_longest("abc", "defgh")) self.pickletest(zip_longest("abc", "defgh", fillvalue=1)) self.pickletest(zip_longest("", "defgh")) def test_bug_7244(self): class Repeater: # this class is similar to itertools.repeat def __init__(self, o, t, e): self.o = o self.t = int(t) self.e = e def __iter__(self): # its iterator is itself return self def __next__(self): if self.t > 0: self.t -= 1 return self.o else: raise self.e # Formerly this code in would fail in debug mode # with Undetected Error and Stop Iteration r1 = Repeater(1, 3, StopIteration) r2 = Repeater(2, 4, StopIteration) def run(r1, r2): result = [] for i, j in zip_longest(r1, r2, fillvalue=0): with support.captured_output('stdout'): print((i, j)) result.append((i, j)) return result self.assertEqual(run(r1, r2), [(1,2), (1,2), (1,2), (0,2)]) # Formerly, the RuntimeError would be lost # and StopIteration would stop as expected r1 = Repeater(1, 3, RuntimeError) r2 = Repeater(2, 4, StopIteration) it = zip_longest(r1, r2, fillvalue=0) self.assertEqual(next(it), (1, 2)) self.assertEqual(next(it), (1, 2)) self.assertEqual(next(it), (1, 2)) self.assertRaises(RuntimeError, next, it) def test_product(self): for args, result in [ ([], [()]), # zero iterables (['ab'], [('a',), ('b',)]), # one iterable ([range(2), range(3)], [(0,0), (0,1), (0,2), (1,0), (1,1), (1,2)]), # two iterables ([range(0), range(2), range(3)], []), # first iterable with zero length ([range(2), range(0), range(3)], []), # middle iterable with zero length ([range(2), range(3), range(0)], []), # last iterable with zero length ]: self.assertEqual(list(product(*args)), result) for r in range(4): self.assertEqual(list(product(*(args*r))), list(product(*args, **dict(repeat=r)))) self.assertEqual(len(list(product(*[range(7)]*6))), 7**6) self.assertRaises(TypeError, product, range(6), None) def product1(*args, **kwds): pools = list(map(tuple, args)) * kwds.get('repeat', 1) n = len(pools) if n == 0: yield () return if any(len(pool) == 0 for pool in pools): return indices = [0] * n yield tuple(pool[i] for pool, i in zip(pools, indices)) while 1: for i in reversed(range(n)): # right to left if indices[i] == len(pools[i]) - 1: continue indices[i] += 1 for j in range(i+1, n): indices[j] = 0 yield tuple(pool[i] for pool, i in zip(pools, indices)) break else: return def product2(*args, **kwds): 'Pure python version used in docs' pools = list(map(tuple, args)) * kwds.get('repeat', 1) result = [[]] for pool in pools: result = [x+[y] for x in result for y in pool] for prod in result: yield tuple(prod) argtypes = ['', 'abc', '', range(0), range(4), dict(a=1, b=2, c=3), set('abcdefg'), range(11), tuple(range(13))] for i in range(100): args = [random.choice(argtypes) for j in range(random.randrange(5))] expected_len = prod(map(len, args)) self.assertEqual(len(list(product(*args))), expected_len) self.assertEqual(list(product(*args)), list(product1(*args))) self.assertEqual(list(product(*args)), list(product2(*args))) args = map(iter, args) self.assertEqual(len(list(product(*args))), expected_len) @support.impl_detail("tuple reuse is specific to CPython") def test_product_tuple_reuse(self): self.assertEqual(len(set(map(id, product('abc', 'def')))), 1) self.assertNotEqual(len(set(map(id, list(product('abc', 'def'))))), 1) def test_product_pickling(self): # check copy, deepcopy, pickle for args, result in [ ([], [()]), # zero iterables (['ab'], [('a',), ('b',)]), # one iterable ([range(2), range(3)], [(0,0), (0,1), (0,2), (1,0), (1,1), (1,2)]), # two iterables ([range(0), range(2), range(3)], []), # first iterable with zero length ([range(2), range(0), range(3)], []), # middle iterable with zero length ([range(2), range(3), range(0)], []), # last iterable with zero length ]: self.assertEqual(list(copy.copy(product(*args))), result) self.assertEqual(list(copy.deepcopy(product(*args))), result) self.pickletest(product(*args)) def test_repeat(self): self.assertEqual(list(repeat(object='a', times=3)), ['a', 'a', 'a']) self.assertEqual(lzip(range(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)') # check copy, deepcopy, pickle c = repeat(object='a', times=10) self.assertEqual(next(c), 'a') self.assertEqual(take(2, copy.copy(c)), list('a' * 2)) self.assertEqual(take(2, copy.deepcopy(c)), list('a' * 2)) self.pickletest(repeat(object='a', times=10)) def test_map(self): self.assertEqual(list(map(operator.pow, range(3), range(1,7))), [0**1, 1**2, 2**3]) self.assertEqual(list(map(tupleize, 'abc', range(5))), [('a',0),('b',1),('c',2)]) self.assertEqual(list(map(tupleize, 'abc', count())), [('a',0),('b',1),('c',2)]) self.assertEqual(take(2,map(tupleize, 'abc', count())), [('a',0),('b',1)]) self.assertEqual(list(map(operator.pow, [])), []) self.assertRaises(TypeError, map) self.assertRaises(TypeError, list, map(None, range(3), range(3))) self.assertRaises(TypeError, map, operator.neg) self.assertRaises(TypeError, next, map(10, range(5))) self.assertRaises(ValueError, next, map(errfunc, [4], [5])) self.assertRaises(TypeError, next, map(onearg, [4], [5])) # check copy, deepcopy, pickle ans = [('a',0),('b',1),('c',2)] c = map(tupleize, 'abc', count()) self.assertEqual(list(copy.copy(c)), ans) c = map(tupleize, 'abc', count()) self.assertEqual(list(copy.deepcopy(c)), ans) c = map(tupleize, 'abc', count()) self.pickletest(c) 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, zip(count(), count(1)))), [0**1, 1**2, 2**3]) self.assertEqual(list(starmap(operator.pow, [])), []) self.assertEqual(list(starmap(operator.pow, [iter([4,5])])), [4**5]) self.assertRaises(TypeError, list, starmap(operator.pow, [None])) self.assertRaises(TypeError, starmap) self.assertRaises(TypeError, starmap, operator.pow, [(4,5)], 'extra') self.assertRaises(TypeError, next, starmap(10, [(4,5)])) self.assertRaises(ValueError, next, starmap(errfunc, [(4,5)])) self.assertRaises(TypeError, next, starmap(onearg, [(4,5)])) # check copy, deepcopy, pickle ans = [0**1, 1**2, 2**3] c = starmap(operator.pow, zip(range(3), range(1,7))) self.assertEqual(list(copy.copy(c)), ans) c = starmap(operator.pow, zip(range(3), range(1,7))) self.assertEqual(list(copy.deepcopy(c)), ans) c = starmap(operator.pow, zip(range(3), range(1,7))) self.pickletest(c) 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(range(100), *args)), list(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(range(100), *args)), list(range(*tgtargs))) # Test stop=None self.assertEqual(list(islice(range(10), None)), list(range(10))) self.assertEqual(list(islice(range(10), None, None)), list(range(10))) self.assertEqual(list(islice(range(10), None, None, None)), list(range(10))) self.assertEqual(list(islice(range(10), 2, None)), list(range(2, 10))) self.assertEqual(list(islice(range(10), 1, None, 2)), list(range(1, 10, 2))) # Test number of items consumed SF #1171417 it = iter(range(10)) self.assertEqual(list(islice(it, 3)), list(range(3))) self.assertEqual(list(it), list(range(3, 10))) # Test invalid arguments ra = range(10) self.assertRaises(TypeError, islice, ra) self.assertRaises(TypeError, islice, ra, 1, 2, 3, 4) self.assertRaises(ValueError, islice, ra, -5, 10, 1) self.assertRaises(ValueError, islice, ra, 1, -5, -1) self.assertRaises(ValueError, islice, ra, 1, 10, -1) self.assertRaises(ValueError, islice, ra, 1, 10, 0) self.assertRaises(ValueError, islice, ra, 'a') self.assertRaises(ValueError, islice, ra, 'a', 1) self.assertRaises(ValueError, islice, ra, 1, 'a') self.assertRaises(ValueError, islice, ra, 'a', 1, 1) self.assertRaises(ValueError, islice, ra, 1, 'a', 1) self.assertEqual(len(list(islice(count(), 1, 10, maxsize))), 1) # Issue #10323: Less islice in a predictable state c = count() self.assertEqual(list(islice(c, 1, 3, 50)), [1]) self.assertEqual(next(c), 3) # check copy, deepcopy, pickle for args in [ # islice(args) should agree with range(args) (10, 20, 3), (10, 3, 20), (10, 20), (10, 3), (20,) ]: self.assertEqual(list(copy.copy(islice(range(100), *args))), list(range(*args))) self.assertEqual(list(copy.deepcopy(islice(range(100), *args))), list(range(*args))) self.pickletest(islice(range(100), *args)) def test_takewhile(self): data = [1, 3, 5, 20, 2, 4, 6, 8] 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, next, takewhile(10, [(4,5)])) self.assertRaises(ValueError, next, takewhile(errfunc, [(4,5)])) t = takewhile(bool, [1, 1, 1, 0, 0, 0]) self.assertEqual(list(t), [1, 1, 1]) self.assertRaises(StopIteration, next, t) # check copy, deepcopy, pickle self.assertEqual(list(copy.copy(takewhile(underten, data))), [1, 3, 5]) self.assertEqual(list(copy.deepcopy(takewhile(underten, data))), [1, 3, 5]) self.pickletest(takewhile(underten, data)) def test_dropwhile(self): data = [1, 3, 5, 20, 2, 4, 6, 8] 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, next, dropwhile(10, [(4,5)])) self.assertRaises(ValueError, next, dropwhile(errfunc, [(4,5)])) # check copy, deepcopy, pickle self.assertEqual(list(copy.copy(dropwhile(underten, data))), [20, 2, 4, 6, 8]) self.assertEqual(list(copy.deepcopy(dropwhile(underten, data))), [20, 2, 4, 6, 8]) self.pickletest(dropwhile(underten, data)) def test_tee(self): n = 200 a, b = tee([]) # test empty iterator self.assertEqual(list(a), []) self.assertEqual(list(b), []) a, b = tee(irange(n)) # test 100% interleaved self.assertEqual(lzip(a,b), lzip(range(n), range(n))) a, b = tee(irange(n)) # test 0% interleaved self.assertEqual(list(a), list(range(n))) self.assertEqual(list(b), list(range(n))) a, b = tee(irange(n)) # test dealloc of leading iterator for i in range(100): self.assertEqual(next(a), i) del a self.assertEqual(list(b), list(range(n))) a, b = tee(irange(n)) # test dealloc of trailing iterator for i in range(100): self.assertEqual(next(a), i) del b self.assertEqual(list(a), list(range(100, n))) for j in range(5): # test randomly interleaved order = [0]*n + [1]*n random.shuffle(order) lists = ([], []) its = tee(irange(n)) for i in order: value = next(its[i]) lists[i].append(value) self.assertEqual(lists[0], list(range(n))) self.assertEqual(lists[1], list(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(range(2000), 3) for i in range(100): self.assertEqual(next(a), i) self.assertEqual(list(b), list(range(2000))) self.assertEqual([next(c), next(c)], list(range(2))) self.assertEqual(list(a), list(range(100,2000))) self.assertEqual(list(c), list(range(2,2000))) # test values of n self.assertRaises(TypeError, tee, 'abc', 'invalid') self.assertRaises(ValueError, tee, [], -1) for n in range(5): result = tee('abc', n) self.assertEqual(type(result), tuple) self.assertEqual(len(result), n) self.assertEqual([list(x) for x in result], [list('abc')]*n) # tee pass-through to copyable iterator a, b = tee('abc') c, d = tee(a) self.assertTrue(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.assertTrue(list(t1) == list(t2) == list(t3) == list('abc')) # test that tee objects are weak referencable a, b = tee(range(10)) p = proxy(a) self.assertEqual(getattr(p, '__class__'), type(b)) del a self.assertRaises(ReferenceError, getattr, p, '__class__') ans = list('abc') long_ans = list(range(10000)) # check copy a, b = tee('abc') self.assertEqual(list(copy.copy(a)), ans) self.assertEqual(list(copy.copy(b)), ans) a, b = tee(list(range(10000))) self.assertEqual(list(copy.copy(a)), long_ans) self.assertEqual(list(copy.copy(b)), long_ans) # check partially consumed copy a, b = tee('abc') take(2, a) take(1, b) self.assertEqual(list(copy.copy(a)), ans[2:]) self.assertEqual(list(copy.copy(b)), ans[1:]) self.assertEqual(list(a), ans[2:]) self.assertEqual(list(b), ans[1:]) a, b = tee(range(10000)) take(100, a) take(60, b) self.assertEqual(list(copy.copy(a)), long_ans[100:]) self.assertEqual(list(copy.copy(b)), long_ans[60:]) self.assertEqual(list(a), long_ans[100:]) self.assertEqual(list(b), long_ans[60:]) # check deepcopy a, b = tee('abc') self.assertEqual(list(copy.deepcopy(a)), ans) self.assertEqual(list(copy.deepcopy(b)), ans) self.assertEqual(list(a), ans) self.assertEqual(list(b), ans) a, b = tee(range(10000)) self.assertEqual(list(copy.deepcopy(a)), long_ans) self.assertEqual(list(copy.deepcopy(b)), long_ans) self.assertEqual(list(a), long_ans) self.assertEqual(list(b), long_ans) # check partially consumed deepcopy a, b = tee('abc') take(2, a) take(1, b) self.assertEqual(list(copy.deepcopy(a)), ans[2:]) self.assertEqual(list(copy.deepcopy(b)), ans[1:]) self.assertEqual(list(a), ans[2:]) self.assertEqual(list(b), ans[1:]) a, b = tee(range(10000)) take(100, a) take(60, b) self.assertEqual(list(copy.deepcopy(a)), long_ans[100:]) self.assertEqual(list(copy.deepcopy(b)), long_ans[60:]) self.assertEqual(list(a), long_ans[100:]) self.assertEqual(list(b), long_ans[60:]) # check pickle self.pickletest(iter(tee('abc'))) a, b = tee('abc') self.pickletest(a, compare=ans) self.pickletest(b, compare=ans) # Issue 13454: Crash when deleting backward iterator from tee() def test_tee_del_backward(self): forward, backward = tee(repeat(None, 20000000)) any(forward) # exhaust the iterator del backward def test_StopIteration(self): self.assertRaises(StopIteration, next, zip()) for f in (chain, cycle, zip, groupby): self.assertRaises(StopIteration, next, f([])) self.assertRaises(StopIteration, next, f(StopNow())) self.assertRaises(StopIteration, next, islice([], None)) self.assertRaises(StopIteration, next, islice(StopNow(), None)) p, q = tee([]) self.assertRaises(StopIteration, next, p) self.assertRaises(StopIteration, next, q) p, q = tee(StopNow()) self.assertRaises(StopIteration, next, p) self.assertRaises(StopIteration, next, q) self.assertRaises(StopIteration, next, repeat(None, 0)) for f in (filter, filterfalse, map, takewhile, dropwhile, starmap): self.assertRaises(StopIteration, next, f(lambda x:x, [])) self.assertRaises(StopIteration, next, f(lambda x:x, StopNow())) class TestExamples(unittest.TestCase): def test_accumulate(self): self.assertEqual(list(accumulate([1,2,3,4,5])), [1, 3, 6, 10, 15]) def test_accumulate_reducible(self): # check copy, deepcopy, pickle data = [1, 2, 3, 4, 5] accumulated = [1, 3, 6, 10, 15] it = accumulate(data) self.assertEqual(list(pickle.loads(pickle.dumps(it))), accumulated[:]) self.assertEqual(next(it), 1) self.assertEqual(list(pickle.loads(pickle.dumps(it))), accumulated[1:]) self.assertEqual(list(copy.deepcopy(it)), accumulated[1:]) self.assertEqual(list(copy.copy(it)), accumulated[1:]) def test_chain(self): self.assertEqual(''.join(chain('ABC', 'DEF')), 'ABCDEF') def test_chain_from_iterable(self): self.assertEqual(''.join(chain.from_iterable(['ABC', 'DEF'])), 'ABCDEF') def test_combinations(self): self.assertEqual(list(combinations('ABCD', 2)), [('A','B'), ('A','C'), ('A','D'), ('B','C'), ('B','D'), ('C','D')]) self.assertEqual(list(combinations(range(4), 3)), [(0,1,2), (0,1,3), (0,2,3), (1,2,3)]) def test_combinations_with_replacement(self): self.assertEqual(list(combinations_with_replacement('ABC', 2)), [('A','A'), ('A','B'), ('A','C'), ('B','B'), ('B','C'), ('C','C')]) 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]) def test_cycle(self): self.assertEqual(list(islice(cycle('ABCD'), 12)), list('ABCDABCDABCD')) def test_dropwhile(self): self.assertEqual(list(dropwhile(lambda x: x<5, [1,4,6,4,1])), [6,4,1]) def test_groupby(self): self.assertEqual([k for k, g in groupby('AAAABBBCCDAABBB')], list('ABCDAB')) self.assertEqual([(list(g)) for k, g in groupby('AAAABBBCCD')], [list('AAAA'), list('BBB'), list('CC'), list('D')]) def test_filter(self): self.assertEqual(list(filter(lambda x: x%2, range(10))), [1,3,5,7,9]) def test_filterfalse(self): self.assertEqual(list(filterfalse(lambda x: x%2, range(10))), [0,2,4,6,8]) def test_map(self): self.assertEqual(list(map(pow, (2,3,10), (5,2,3))), [32, 9, 1000]) def test_islice(self): self.assertEqual(list(islice('ABCDEFG', 2)), list('AB')) self.assertEqual(list(islice('ABCDEFG', 2, 4)), list('CD')) self.assertEqual(list(islice('ABCDEFG', 2, None)), list('CDEFG')) self.assertEqual(list(islice('ABCDEFG', 0, None, 2)), list('ACEG')) def test_zip(self): self.assertEqual(list(zip('ABCD', 'xy')), [('A', 'x'), ('B', 'y')]) def test_zip_longest(self): self.assertEqual(list(zip_longest('ABCD', 'xy', fillvalue='-')), [('A', 'x'), ('B', 'y'), ('C', '-'), ('D', '-')]) def test_permutations(self): self.assertEqual(list(permutations('ABCD', 2)), list(map(tuple, 'AB AC AD BA BC BD CA CB CD DA DB DC'.split()))) self.assertEqual(list(permutations(range(3))), [(0,1,2), (0,2,1), (1,0,2), (1,2,0), (2,0,1), (2,1,0)]) def test_product(self): self.assertEqual(list(product('ABCD', 'xy')), list(map(tuple, 'Ax Ay Bx By Cx Cy Dx Dy'.split()))) self.assertEqual(list(product(range(2), repeat=3)), [(0,0,0), (0,0,1), (0,1,0), (0,1,1), (1,0,0), (1,0,1), (1,1,0), (1,1,1)]) def test_repeat(self): self.assertEqual(list(repeat(10, 3)), [10, 10, 10]) def test_stapmap(self): self.assertEqual(list(starmap(pow, [(2,5), (3,2), (10,3)])), [32, 9, 1000]) def test_takewhile(self): self.assertEqual(list(takewhile(lambda x: x<5, [1,4,6,4,1])), [1,4]) class TestGC(unittest.TestCase): def makecycle(self, iterator, container): container.append(iterator) next(iterator) del container, iterator def test_accumulate(self): a = [] self.makecycle(accumulate([1,2,a,3]), a) def test_chain(self): a = [] self.makecycle(chain(a), a) def test_chain_from_iterable(self): a = [] self.makecycle(chain.from_iterable([a]), a) def test_combinations(self): a = [] self.makecycle(combinations([1,2,a,3], 3), a) def test_combinations_with_replacement(self): a = [] self.makecycle(combinations_with_replacement([1,2,a,3], 3), a) def test_compress(self): a = [] self.makecycle(compress('ABCDEF', [1,0,1,0,1,0]), a) def test_count(self): a = [] Int = type('Int', (int,), dict(x=a)) self.makecycle(count(Int(0), Int(1)), 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_issue2246(self): # Issue 2246 -- the _grouper iterator was not included in GC n = 10 keyfunc = lambda x: x for i, j in groupby(range(n), key=keyfunc): keyfunc.__dict__.setdefault('x',[]).append(j) def test_filter(self): a = [] self.makecycle(filter(lambda x:True, [a]*2), a) def test_filterfalse(self): a = [] self.makecycle(filterfalse(lambda x:False, a), a) def test_zip(self): a = [] self.makecycle(zip([a]*2, [a]*3), a) def test_zip_longest(self): a = [] self.makecycle(zip_longest([a]*2, [a]*3), a) b = [a, None] self.makecycle(zip_longest([a]*2, [a]*3, fillvalue=b), a) def test_map(self): a = [] self.makecycle(map(lambda x:x, [a]*2), a) def test_islice(self): a = [] self.makecycle(islice([a]*2, None), a) def test_permutations(self): a = [] self.makecycle(permutations([1,2,a,3], 3), a) def test_product(self): a = [] self.makecycle(product([1,2,a,3], repeat=3), 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(map(lambda x:x, R(Ig(G(seqn))))) class TestVariousIteratorArgs(unittest.TestCase): def test_accumulate(self): s = [1,2,3,4,5] r = [1,3,6,10,15] n = len(s) for g in (G, I, Ig, L, R): self.assertEqual(list(accumulate(g(s))), r) self.assertEqual(list(accumulate(S(s))), []) self.assertRaises(TypeError, accumulate, X(s)) self.assertRaises(TypeError, accumulate, N(s)) self.assertRaises(ZeroDivisionError, list, accumulate(E(s))) def test_chain(self): for s in ("123", "", range(1000), ('do', 1.2), range(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, list, chain(X(s))) 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), range(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, 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), range(2000,2200,5)): self.assertRaises(TypeError, product, X(s)) self.assertRaises(TypeError, product, N(s)) self.assertRaises(ZeroDivisionError, product, E(s)) def test_cycle(self): for s in ("123", "", range(1000), ('do', 1.2), range(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), range(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_filter(self): for s in (range(10), range(0), range(1000), (7,11), range(2000,2200,5)): for g in (G, I, Ig, S, L, R): self.assertEqual(list(filter(isEven, g(s))), [x for x in g(s) if isEven(x)]) self.assertRaises(TypeError, filter, isEven, X(s)) self.assertRaises(TypeError, filter, isEven, N(s)) self.assertRaises(ZeroDivisionError, list, filter(isEven, E(s))) def test_filterfalse(self): for s in (range(10), range(0), range(1000), (7,11), range(2000,2200,5)): for g in (G, I, Ig, S, L, R): self.assertEqual(list(filterfalse(isEven, g(s))), [x for x in g(s) if isOdd(x)]) self.assertRaises(TypeError, filterfalse, isEven, X(s)) self.assertRaises(TypeError, filterfalse, isEven, N(s)) self.assertRaises(ZeroDivisionError, list, filterfalse(isEven, E(s))) def test_zip(self): for s in ("123", "", range(1000), ('do', 1.2), range(2000,2200,5)): for g in (G, I, Ig, S, L, R): self.assertEqual(list(zip(g(s))), lzip(g(s))) self.assertEqual(list(zip(g(s), g(s))), lzip(g(s), g(s))) self.assertRaises(TypeError, zip, X(s)) self.assertRaises(TypeError, zip, N(s)) self.assertRaises(ZeroDivisionError, list, zip(E(s))) def test_ziplongest(self): for s in ("123", "", range(1000), ('do', 1.2), range(2000,2200,5)): for g in (G, I, Ig, S, L, R): self.assertEqual(list(zip_longest(g(s))), list(zip(g(s)))) self.assertEqual(list(zip_longest(g(s), g(s))), list(zip(g(s), g(s)))) self.assertRaises(TypeError, zip_longest, X(s)) self.assertRaises(TypeError, zip_longest, N(s)) self.assertRaises(ZeroDivisionError, list, zip_longest(E(s))) def test_map(self): for s in (range(10), range(0), range(100), (7,11), range(20,50,5)): for g in (G, I, Ig, S, L, R): self.assertEqual(list(map(onearg, g(s))), [onearg(x) for x in g(s)]) self.assertEqual(list(map(operator.pow, g(s), g(s))), [x**x for x in g(s)]) self.assertRaises(TypeError, map, onearg, X(s)) self.assertRaises(TypeError, map, onearg, N(s)) self.assertRaises(ZeroDivisionError, list, map(onearg, E(s))) def test_islice(self): for s in ("12345", "", range(1000), ('do', 1.2), range(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), range(20,50,5)): for g in (G, I, Ig, S, L, R): ss = lzip(s, s) self.assertEqual(list(starmap(operator.pow, g(ss))), [x**x for x in 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), range(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), range(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), range(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): self.assertEqual(operator.length_hint(repeat(None, 50)), 50) self.assertEqual(operator.length_hint(repeat(None), 12), 12) 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(next(z)) return value items = list(tuple2) items[1:1] = list(tuple1) gen = map(g, items) z = zip(*[gen]*len(tuple1)) next(z) 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]) class SubclassWithKwargsTest(unittest.TestCase): def test_keywords_in_subclass(self): # count is not subclassable... for cls in (repeat, zip, filter, filterfalse, chain, map, starmap, islice, takewhile, dropwhile, cycle, compress): class Subclass(cls): def __init__(self, newarg=None, *args): cls.__init__(self, *args) try: Subclass(newarg=1) except TypeError as err: # we expect type errors because of wrong argument count self.assertNotIn("does not take keyword arguments", err.args[0]) @support.cpython_only class SizeofTest(unittest.TestCase): def setUp(self): self.ssize_t = struct.calcsize('n') check_sizeof = support.check_sizeof def test_product_sizeof(self): basesize = support.calcobjsize('3Pi') check = self.check_sizeof check(product('ab', '12'), basesize + 2 * self.ssize_t) check(product(*(('abc',) * 10)), basesize + 10 * self.ssize_t) def test_combinations_sizeof(self): basesize = support.calcobjsize('3Pni') check = self.check_sizeof check(combinations('abcd', 3), basesize + 3 * self.ssize_t) check(combinations(range(10), 4), basesize + 4 * self.ssize_t) def test_combinations_with_replacement_sizeof(self): cwr = combinations_with_replacement basesize = support.calcobjsize('3Pni') check = self.check_sizeof check(cwr('abcd', 3), basesize + 3 * self.ssize_t) check(cwr(range(10), 4), basesize + 4 * self.ssize_t) def test_permutations_sizeof(self): basesize = support.calcobjsize('4Pni') check = self.check_sizeof check(permutations('abcd'), basesize + 4 * self.ssize_t + 4 * self.ssize_t) check(permutations('abcd', 3), basesize + 4 * self.ssize_t + 3 * self.ssize_t) check(permutations('abcde', 3), basesize + 5 * self.ssize_t + 3 * self.ssize_t) check(permutations(range(10), 4), basesize + 10 * self.ssize_t + 4 * self.ssize_t) libreftest = """ Doctest for examples in the library reference: libitertools.tex >>> amounts = [120.15, 764.05, 823.14] >>> for checknum, amount in zip(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 map(operator.pow, range(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.items()), key=itemgetter(1)) >>> for k, g in groupby(di, itemgetter(1)): ... print(k, list(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 t:t[0]-t[1]): ... print(list(map(operator.itemgetter(1), g))) ... [1] [4, 5, 6] [10] [15, 16, 17, 18] [22] [25, 26, 27, 28] >>> def take(n, iterable): ... "Return first n items of the iterable as a list" ... return list(islice(iterable, n)) >>> def enumerate(iterable, start=0): ... return zip(count(start), iterable) >>> def tabulate(function, start=0): ... "Return function(0), function(1), ..." ... return map(function, count(start)) >>> def nth(iterable, n, default=None): ... "Returns the nth item or a default value" ... return next(islice(iterable, n, None), default) >>> def quantify(iterable, pred=bool): ... "Count how many times the predicate is true" ... return sum(map(pred, iterable)) >>> def padnone(iterable): ... "Returns the sequence elements and then returns None indefinitely" ... return chain(iterable, repeat(None)) >>> def ncycles(iterable, n): ... "Returns the sequence elements n times" ... return chain(*repeat(iterable, n)) >>> def dotproduct(vec1, vec2): ... return sum(map(operator.mul, vec1, vec2)) >>> def flatten(listOfLists): ... return list(chain.from_iterable(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: ... next(b) ... except StopIteration: ... pass ... return zip(a, b) >>> def grouper(n, iterable, fillvalue=None): ... "grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx" ... args = [iter(iterable)] * n ... return zip_longest(*args, fillvalue=fillvalue) >>> def roundrobin(*iterables): ... "roundrobin('ABC', 'D', 'EF') --> A D E B F C" ... # Recipe credited to George Sakkis ... pending = len(iterables) ... nexts = cycle(iter(it).__next__ for it in iterables) ... while pending: ... try: ... for next in nexts: ... yield next() ... except StopIteration: ... pending -= 1 ... nexts = cycle(islice(nexts, pending)) >>> def powerset(iterable): ... "powerset([1,2,3]) --> () (1,) (2,) (3,) (1,2) (1,3) (2,3) (1,2,3)" ... s = list(iterable) ... return chain.from_iterable(combinations(s, r) for r in range(len(s)+1)) >>> def unique_everseen(iterable, key=None): ... "List unique elements, preserving order. Remember all elements ever seen." ... # unique_everseen('AAAABBBCCDAABBB') --> A B C D ... # unique_everseen('ABBCcAD', str.lower) --> A B C D ... seen = set() ... seen_add = seen.add ... if key is None: ... for element in iterable: ... if element not in seen: ... seen_add(element) ... yield element ... else: ... for element in iterable: ... k = key(element) ... if k not in seen: ... seen_add(k) ... yield element >>> def unique_justseen(iterable, key=None): ... "List unique elements, preserving order. Remember only the element just seen." ... # unique_justseen('AAAABBBCCDAABBB') --> A B C D A B ... # unique_justseen('ABBCcAD', str.lower) --> A B C A D ... return map(next, map(itemgetter(1), groupby(iterable, key))) 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' >>> nth('abcde', 9) is None True >>> quantify(range(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, map(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 >>> list(grouper(3, 'abcdefg', 'x')) [('a', 'b', 'c'), ('d', 'e', 'f'), ('g', 'x', 'x')] >>> list(roundrobin('abc', 'd', 'ef')) ['a', 'd', 'e', 'b', 'f', 'c'] >>> list(powerset([1,2,3])) [(), (1,), (2,), (3,), (1, 2), (1, 3), (2, 3), (1, 2, 3)] >>> all(len(list(powerset(range(n)))) == 2**n for n in range(18)) True >>> list(powerset('abcde')) == sorted(sorted(set(powerset('abcde'))), key=len) True >>> list(unique_everseen('AAAABBBCCDAABBB')) ['A', 'B', 'C', 'D'] >>> list(unique_everseen('ABBCcAD', str.lower)) ['A', 'B', 'C', 'D'] >>> list(unique_justseen('AAAABBBCCDAABBB')) ['A', 'B', 'C', 'D', 'A', 'B'] >>> list(unique_justseen('ABBCcAD', str.lower)) ['A', 'B', 'C', 'A', 'D'] """ __test__ = {'libreftest' : libreftest} def test_main(verbose=None): test_classes = (TestBasicOps, TestVariousIteratorArgs, TestGC, RegressionTests, LengthTransparency, SubclassWithKwargsTest, TestExamples, SizeofTest) support.run_unittest(*test_classes) # verify reference counting if verbose and hasattr(sys, "gettotalrefcount"): import gc counts = [None] * 5 for i in range(len(counts)): support.run_unittest(*test_classes) gc.collect() counts[i] = sys.gettotalrefcount() print(counts) # doctest the examples in the library reference support.run_doctest(sys.modules[__name__], verbose) if __name__ == "__main__": test_main(verbose=True)