from copy import copy, deepcopy @tuple class A: a: int b: float def __getitem__(self: A, n: int): return 1 def __getitem__(self: A, x: Slice): if x.start is None and x.stop is None: return -1 if x.start is None: return 2 elif x.stop is None: return 3 else: return self.a @test def test_tuple(): def test_in(): for i in range(10): yield i, i in (4, 9, 10, -1, 3, 1), i in (7,) assert list(test_in()) == [(0, False, False), (1, True, False), (2, False, False), (3, True, False), (4, True, False), (5, False, False), (6, False, False), (7, False, True), (8, False, False), (9, True, False)] def test_cmp[T](a: T, b: T): yield 'EQ', a == b yield 'NE', a != b yield 'LT', a < b yield 'GT', a > b yield 'LE', a <= b yield 'GE', a >= b assert list(test_cmp((1,2), (1,2))) == [('EQ', True), ('NE', False), ('LT', False), ('GT', False), ('LE', True), ('GE', True)] assert list(test_cmp((1,2,2), (1,2,3))) == [('EQ', False), ('NE', True), ('LT', True), ('GT', False), ('LE', True), ('GE', False)] assert list(test_cmp((1,2,-1), (1,0,1))) == [('EQ', False), ('NE', True), ('LT', False), ('GT', True), ('LE', False), ('GE', True)] assert list(test_cmp((), ())) == [('EQ', True), ('NE', False), ('LT', False), ('GT', False), ('LE', True), ('GE', True)] t = (1,2,3) assert (t[0], t[1], t[2]) == (1, 2, 3) assert (t[-1], t[-2], t[-3]) == (3, 2, 1) assert t[1:3] == (2, 3) assert t[-3:1] == (1,) assert t[-10:2] == (1, 2) assert t[0:] == (1, 2, 3) assert t[-2:] == (2, 3) assert t[3:] == () assert t[:-1] == (1, 2) assert t[:1] == (1,) assert t[:] == (1, 2, 3) assert t[1::1] == (2, 3) assert t[:2:1] == (1, 2) assert t[::2] == (1, 3) assert t[::-1] == (3, 2, 1) assert t[0:3:-1] == () assert t[3:0:-1] == (3, 2, 1) a = A(42, 3.14) assert a[0] == 1 assert a[:1] == 2 assert a[0:] == 3 assert a[0:1] == 42 assert a[:] == -1 test_tuple() @test def test_list(): l1 = [i+1 for i in range(100)] assert len(l1) == 100 l1 = l1[98:] l2 = [1, 2] * 2 assert [a for a in l1] == [99, 100] assert [a for a in l2] == [1, 2, 1, 2] l1 = [i*2 for i in range(3)] l1.insert(0, 99) l1[0] += 1 del l1[1] assert [a for a in l1[0:3]] == [100, 2, 4] l3 = [1, 2, 3] assert l3.remove(2) == True assert l3.remove(2) == False assert l3 == [1, 3] assert list[int]().remove(0) == False # l4 = [5, 1, 4, 2, 1, -10, 10, 100, -100] # assert sorted(l4) == [-100, -10, 1, 1, 2, 4, 5, 10, 100] #l4.sort() #assert l4 == [-100, -10, 1, 1, 2, 4, 5, 10, 100] #assert str(sorted(list[int]())) == "[]" l5 = [11, 22, 33, 44] del l5[-1] assert l5 == [11, 22, 33] l5.insert(-1, 55) l5.insert(1000, 66) l5.insert(-100, 77) assert l5 == [77, 11, 22, 55, 33, 66] l5 = [11, 22, 55, 33] assert l5 + [1,2,3] == [11, 22, 55, 33, 1, 2, 3] l5 += [1,2,3] assert l5 == [11, 22, 55, 33, 1, 2, 3] assert l5.pop() == 3 assert l5 * 2 == [11, 22, 55, 33, 1, 2, 11, 22, 55, 33, 1, 2] l5 *= 2 assert l5 == [11, 22, 55, 33, 1, 2, 11, 22, 55, 33, 1, 2] assert l5.index(33) == 3 l5 *= 0 assert len(l5) == 0 l6 = [] l6.extend('abc') l6.extend(['xyz']) l6.extend('') assert l6 == ['a', 'b', 'c', 'xyz'] assert List[int]().copy() == List[int]() assert [1,2,3].copy() == [1,2,3] def test_cmp[T](a: T, b: T): yield 'EQ', a == b yield 'NE', a != b yield 'LT', a < b yield 'GT', a > b yield 'LE', a <= b yield 'GE', a >= b assert list(test_cmp([1,2], [1,2])) == [('EQ', True), ('NE', False), ('LT', False), ('GT', False), ('LE', True), ('GE', True)] assert list(test_cmp([1,2,2], [1,2,3])) == [('EQ', False), ('NE', True), ('LT', True), ('GT', False), ('LE', True), ('GE', False)] assert list(test_cmp([1,2,-1], [1,0,1])) == [('EQ', False), ('NE', True), ('LT', False), ('GT', True), ('LE', False), ('GE', True)] assert list(test_cmp(List[int](), List[int]())) == [('EQ', True), ('NE', False), ('LT', False), ('GT', False), ('LE', True), ('GE', True)] assert list(test_cmp([1], List[int]())) == [('EQ', False), ('NE', True), ('LT', False), ('GT', True), ('LE', False), ('GE', True)] assert list(test_cmp(List[int](), [1])) == [('EQ', False), ('NE', True), ('LT', True), ('GT', False), ('LE', True), ('GE', False)] assert list(test_cmp([1,2,-1], [2])) == [('EQ', False), ('NE', True), ('LT', True), ('GT', False), ('LE', True), ('GE', False)] assert list(test_cmp([1,2,-1], [1,2,-1,3])) == [('EQ', False), ('NE', True), ('LT', True), ('GT', False), ('LE', True), ('GE', False)] assert list(test_cmp([1,2,-1,3], [1,2,-1])) == [('EQ', False), ('NE', True), ('LT', False), ('GT', True), ('LE', False), ('GE', True)] assert str([1] + [2] + [] + [3]) == '[1, 2, 3]' assert ['a', 'b'] + ['x', 'y', 'z'] == ['a', 'b'] + ['x', 'y', 'z'] assert [(1,1), (2,2)] + [] == [(1,1), (2,2)] assert [] + [(1,1), (2,2)] == [(1,1), (2,2)] assert List[int]() + List[int]() == List[int]() l7 = [3.14, 2.5] l7 += [9.99, -1.0] assert l7 == [3.14, 2.5, 9.99, -1.0] l8 = [] l8 += [11, 22, 33] assert l8 == [11, 22, 33] l8 = [11, 22, 33] l8 += [] assert l8 == [11, 22, 33] l8 = List[int]() l8 += List[int]() assert l8 == List[int]() test_list() @test def test_setslice(): l = [0, 1] a = l for i in range(-3, 4): a[:i] = l[:i] assert a == l a2 = a[:] a2[:i] = a[:i] assert a2 == a a[i:] = l[i:] assert a == l a2 = a[:] a2[i:] = a[i:] assert a2 == a for j in range(-3, 4): a[i:j] = l[i:j] assert a == l a2 = a[:] a2[i:j] = a[i:j] assert a2 == a a2 = a[:] aa2 = a2[:] aa2[:0] = [-2, -1] assert aa2 == [-2, -1, 0, 1] aa2[0:] = list[int]() assert aa2 == list[int]() a = [1, 2, 3, 4, 5] a[:-1] = a assert a == [1, 2, 3, 4, 5, 5] a = [1, 2, 3, 4, 5] a[1:] = a assert a == [1, 1, 2, 3, 4, 5] a = [1, 2, 3, 4, 5] a[1:-1] = a assert a == [1, 1, 2, 3, 4, 5, 5] a = list[int]() a[:] = list(range(10)) assert a == list(range(10)) a = list(range(20)) try: a[0:10:0] = [1,2,3] assert False except ValueError: pass try: a[0:10:2] = [1,2] assert False except ValueError: pass a[2:10:3] = [1,2,3] assert a == [0, 1, 1, 3, 4, 2, 6, 7, 3, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19] test_setslice() @test def test_delslice(): a = [0, 1] del a[1:2] del a[0:1] assert a == list[int]() a = [0, 1] del a[1:2] del a[0:1] assert a == list[int]() a = [0, 1] del a[-2:-1] assert a == [1] a = [0, 1] del a[-2:-1] assert a == [1] a = [0, 1] del a[1:] del a[:1] assert a == list[int]() a = [0, 1] del a[1:] del a[:1] assert a == list[int]() a = [0, 1] del a[-1:] assert a == [0] a = [0, 1] del a[-1:] assert a == [0] a = [0,1] del a[:] assert a == list[int]() test_delslice() @test def test_extendedslicing(): a = [0,1,2,3,4] del a[::2] assert a == [1,3] a = list(range(5)) del a[1::2] assert a == [0,2,4] a = list(range(5)) del a[1::-2] assert a == [0,2,3,4] a = list(range(10)) del a[::1000] assert a == [1, 2, 3, 4, 5, 6, 7, 8, 9] a = list(range(10)) a[::2] = [-1]*5 assert a == [-1, 1, -1, 3, -1, 5, -1, 7, -1, 9] a = list(range(10)) a[::-4] = [10]*3 assert a == [0, 10, 2, 3, 4, 10, 6, 7, 8 ,10] a = list(range(4)) a[::-1] = a assert a == [3, 2, 1, 0] a = list(range(10)) b = a[:] c = a[:] a[2:3] = [222, 333] b[2:3] = [222, 333] c[2:3:] = [222, 333] assert a == b assert a == c a = list(range(10)) a[::2] = (0, 1, 2, 3, 4) assert a == [0, 1, 1, 3, 2, 5, 3, 7, 4, 9] assert repr(['x', 'y', 'z']) == "['x', 'y', 'z']" assert repr(List[int]()) == '[]' test_extendedslicing() @test def test_set(): s1 = {a for a in range(100)} assert len(s1) == 100 s1 = {a%8 for a in range(100)} for a in range(8): assert a in s1 for a in range(8,100): assert a not in s1 assert 5 in s1 s1.remove(5) assert 5 not in s1 assert len(s1) == 7 s1 = {1,2,3,4} s2 = {2,3,4,5} s3 = set[int]() assert (s1 | s2) == {1, 2, 3, 4, 5} assert (s1 & s2) == {4, 2, 3} assert (s1 ^ s2) == {1, 5} assert (s1 | s3) == {1, 2, 3, 4} assert (s1 & s3) == set[int]() assert (s1 ^ s3) == {1, 2, 3, 4} assert (s1 - s2) == {1} assert (s2 - s1) == {5} assert (s3 - s1 - s2) == set[int]() assert (s1 > s2) == False assert (s1 < s2) == False assert (s3 <= s1) == True assert (s2 >= s1) == False assert ((s1 | s2) > s1) == True s1c = copy(s1) s2c = copy(s2) s3c = copy(s3) assert s1c == {1, 2, 3, 4} s1c &= s2c assert s1c == {2, 3, 4} s1c -= s3c assert s1c == {2, 3, 4} s1c ^= s1c assert s1c == set[int]() s1c |= s2c assert s1c == {2, 3, 4, 5} assert s1 == {1, 2, 3, 4} s1 = {1, 2, 3, 999999} s2 = {1, 2, 3, 999999} v = s1.pop() assert v in s2 s2.remove(v) v = s1.pop() assert v in s2 s2.remove(v) v = s1.pop() assert v in s2 s2.remove(v) v = s1.pop() assert v in s2 s2.remove(v) try: s1.pop() assert False except ValueError: pass assert repr({(1,2)}) == '{(1, 2)}' assert repr(Set[int]()) == 'set()' test_set() @test def test_dict(): d1 = copy({a: a*a for a in range(100)}) assert len(d1) == 100 d1 = {a: a*a for a in range(5)} assert len(copy(dict[int,int]())) == 0 assert [d1.get(a, -1) for a in range(6)] == [0, 1, 4, 9, 16, -1] assert 2 in d1 del d1[2] assert 2 not in d1 d1[2] = 44 assert 2 in d1 assert d1.get(2, -1) == 44 assert d1[3] == 9 del d1[3] del d1[4] assert [k for k in d1] == [0, 1, 2] assert [t for t in d1.items()] == [(0, 0), (1, 1), (2, 44)] d2 = {'x': 10, 'y': 0} d2.increment('x') d2.increment('y', by=-1) d2.increment('z', by=2) assert d2['x'] == 11 assert d2['y'] == -1 assert d2['z'] == 2 assert d2 == {'x': 11, 'y': -1, 'z': 2} d3 = {1: 2, 42: 42} d4 = {1: 5, 2: 9} assert d3 | d4 == {1: 5, 42: 42, 2: 9} d3 |= d4 assert d3 == {1: 5, 42: 42, 2: 9} assert repr({1: ['x']}) == "{1: ['x']}" assert repr(Dict[int,int]()) == '{}' test_dict() @test def test_deque(): from collections import deque dq = deque[int]() dq.append(1) dq.append(2) dq.append(3) dq.appendleft(11) dq.appendleft(22) assert str(dq) == 'deque([22, 11, 1, 2, 3])' assert bool(dq) == True # test cap increase: dq.clear() assert bool(dq) == False for i in range(20): dq.append(i) dq.appendleft(i) assert str(dq) == 'deque([19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19])' assert len(dq) == 40 for i in range(19): dq.pop() dq.popleft() assert str(dq) == 'deque([0, 0])' for a in dq: assert a == 0 assert (0 in dq) == True assert (1 in dq) == False assert str(copy(dq)) == 'deque([0, 0])' # test maxlen: dq = deque[int](5) for i in range(100): dq.append(i) assert str(dq) == 'deque([95, 96, 97, 98, 99])' for i in range(5): dq.append(i) assert str(dq) == 'deque([0, 1, 2, 3, 4])' test_deque() @test def test_counter(): from collections import Counter # main c = Counter('abcaba') assert c == Counter({'a':3 , 'b': 2, 'c': 1}) assert len(c) == 3 assert sum(c.values()) == 6 assert set(c.values()) == {1, 2, 3} assert set(c.keys()) == {'a','b','c'} assert set(c.items()) == {('a',3), ('b',2), ('c',1)} assert c['b'] == 2 assert c['z'] == 0 assert c.__contains__('b') assert not c.__contains__('z') assert c.get('b', 10) == 2 assert c.get('z', 10) == 10 assert c == {'a':3 , 'b': 2, 'c': 1} assert c.most_common() == [('a', 3), ('b', 2), ('c', 1)] for i in range(5): assert c.most_common(i) == [('a', 3), ('b', 2), ('c', 1)][:i] c['a'] += 1 # increment an existing value c['b'] -= 2 # sub existing value to zero del c['c'] # remove an entry del c['c'] # make sure that del doesn't raise KeyError c['d'] -= 2 # sub from a missing value c['e'] = -5 # directly assign a missing value c['f'] += 4 # add to a missing value assert dict(c) == {'a':4, 'b':0, 'd':-2, 'e':-5, 'f':4} assert c.pop('f') == 4 assert 'f' not in c for i in range(3): elem, cnt = c.popitem() assert elem not in c c.clear() assert c == {} c.update({'a':5, 'b':3}) c.update({'c': 1}) c.update(Counter('a' * 50 + 'b' * 30)) c.update() c.update('a' * 500 + 'b' * 300) c.update('cdc') assert c == {'a':555, 'b':333, 'c':3, 'd':1} assert c.setdefault('d',5) == 1 assert c['d'] == 1 assert c.setdefault('e', 5) == 5 assert c['e'] == 5 # total c = Counter({'a':10, 'b':5, 'c':0}) assert c.total() == 15 # conversions s = 'she sells sea shells by the sea shore' assert sorted(Counter(s).elements()) == sorted(s) assert sorted(Counter(s)) == sorted(set(s)) assert dict(Counter(s)) == dict(Counter(s).items()) assert set(Counter(s)) == set(s) # in invariant c = Counter({'a':10, 'b':-2, 'c':0}) for elem in c: assert elem in c # multiset c = Counter({'a':10, 'b':-2, 'c':0}) + Counter() assert dict(c) == {'a':10} from random import randrange, randint elements = 'abcd' for i in range(1000): # test random pairs of multisets p = Counter(dict((elem, randrange(-2,4)) for elem in elements)) p.update({'e':1, 'f':-1, 'g':0}) q = Counter(dict((elem, randrange(-2,4)) for elem in elements)) q.update({'h':1, 'i':-1, 'j':0}) result = p + q for x in elements: assert max(0, p[x] + q[x]) == result[x] assert all(x>0 for x in result.values()) result = p - q for x in elements: assert max(0, p[x] - q[x]) == result[x] assert all(x>0 for x in result.values()) result = p | q for x in elements: assert max(0, p[x], q[x]) == result[x] assert all(x>0 for x in result.values()) result = p & q for x in elements: assert max(0, min(p[x], q[x])) == result[x] assert all(x>0 for x in result.values()) elements = 'abcdef' for i in range(100): # verify that random multisets with no repeats are exactly like sets p = Counter(dict((elem, randrange(0, 2)) for elem in elements)) q = Counter(dict((elem, randrange(0, 2)) for elem in elements)) counter_result = p - q set_result = set(p.elements()) - set(q.elements()) assert counter_result == dict.fromkeys(set_result, 1) counter_result = p | q set_result = set(p.elements()) | set(q.elements()) assert counter_result == dict.fromkeys(set_result, 1) counter_result = p & q set_result = set(p.elements()) & set(q.elements()) assert counter_result == dict.fromkeys(set_result, 1) # in-place elements = 'abcd' for i in range(1000): # test random pairs of multisets p = Counter(dict((elem, randrange(-2,4)) for elem in elements)) p.update({'e':1, 'f':-1, 'g':0}) q = Counter(dict((elem, randrange(-2,4)) for elem in elements)) q.update({'h':1, 'i':-1, 'j':0}) c = p.copy() c_id = id(c) regular_result = c + q inplace_result = c.__iadd__(q) assert inplace_result == regular_result assert id(inplace_result) == c_id c = p.copy() c_id = id(c) regular_result = c - q inplace_result = c.__isub__(q) assert inplace_result == regular_result assert id(inplace_result) == c_id c = p.copy() c_id = id(c) regular_result = c | q inplace_result = c.__ior__(q) assert inplace_result == regular_result assert id(inplace_result) == c_id c = p.copy() c_id = id(c) regular_result = c & q inplace_result = c.__iand__(q) assert inplace_result == regular_result assert id(inplace_result) == c_id # subtract c = Counter({'a':-5, 'b':0, 'c':5, 'd':10, 'e':15,'g':40}) c.subtract({'a':1, 'b':2, 'c':-3, 'd':10, 'e':20, 'f':30, 'h':-50}) assert c == Counter({'a':-6, 'b':-2, 'c':8, 'd':0, 'e':-5, 'f':-30, 'g':40, 'h':50}) c = Counter({'a':-5, 'b':0, 'c':5, 'd':10, 'e':15,'g':40}) c.subtract(Counter({'a':1, 'b':2, 'c':-3, 'd':10, 'e':20, 'f':30, 'h':-50})) assert c == Counter({'a':-6, 'b':-2, 'c':8, 'd':0, 'e':-5, 'f':-30, 'g':40, 'h':50}) c = Counter('aaabbcd') c.subtract('aaaabbcce') assert c == Counter({'a':-1, 'b':0, 'c':-1, 'd':1, 'e':-1}) c = Counter() c.subtract({'self':42}) assert list(c.items()) == [('self', -42)] c = Counter() c.subtract({'iterable':42}) assert list(c.items()) == [('iterable', -42)] # unary c = Counter({'a':-5, 'b':0, 'c':5, 'd':10, 'e':15, 'g':40}) assert dict(+c) == {'c':5, 'd':10, 'e':15, 'g':40} assert dict(-c) == {'a':5} # equality assert Counter({'a':3, 'b':2}) == Counter('ababa') assert Counter({'a':3, 'b':2}) != Counter('babab') # most common c = Counter({v:k for k,v in enumerate('hgfedcba')}) q = [(v,k) for k,v in enumerate('hgfedcba')][::-1] assert c.most_common() == q for i in range(10): assert c.most_common(i) == q[:i] for limit in range(100): for samples in range(100): for most_common in range(100): data = [randint(0, limit) for _ in range(samples)] d = Counter(data) exp = sorted(d.values(), reverse=True)[:most_common] got = [v for k,v in d.most_common(most_common)] assert exp == got for limit in range(100): for samples in range(100): data = [randint(0, limit) for _ in range(samples)] d = Counter(data) exp = sorted(d.values(), reverse=True) got = [v for k,v in d.most_common()] assert exp == got assert repr(Counter('abcabc')) == "Counter({'a': 2, 'b': 2, 'c': 2})" test_counter() @test def test_defaultdict(): from collections import defaultdict # basic #d1 = defaultdict() #self.assertEqual(d1.default_factory, None) #d1.default_factory = list d1 = defaultdict(list) d1[12].append(42) assert d1 == {12: [42]} d1[12].append(24) assert d1 == {12: [42, 24]} d1[13] d1[14] assert d1 == {12: [42, 24], 13: [], 14: []} assert d1[12] is not d1[13] is not d1[14] #d2 = defaultdict(list, foo=1, bar=2) #self.assertEqual(d2.default_factory, list) #self.assertEqual(d2, {"foo": 1, "bar": 2}) #self.assertEqual(d2["foo"], 1) #self.assertEqual(d2["bar"], 2) #self.assertEqual(d2[42], []) #self.assertIn("foo", d2) #self.assertIn("foo", d2.keys()) #self.assertIn("bar", d2) #self.assertIn("bar", d2.keys()) #self.assertIn(42, d2) #self.assertIn(42, d2.keys()) #self.assertNotIn(12, d2) #self.assertNotIn(12, d2.keys()) #d2.default_factory = None #self.assertEqual(d2.default_factory, None) #try: # d2[15] #except KeyError as err: # self.assertEqual(err.args, (15,)) #else: # self.fail("d2[15] didn't raise KeyError") #self.assertRaises(TypeError, defaultdict, 1) # missing #d1 = defaultdict() #self.assertRaises(KeyError, d1.__missing__, 42) #d1.default_factory = list #d1 = defaultdict(list) assert d1.__missing__(42) == [] # repr d1 = defaultdict(lambda: 0) #self.assertEqual(d1.default_factory, None) #self.assertEqual(repr(d1), "defaultdict(None, {})") #self.assertEqual(eval(repr(d1)), d1) d1[11] = 41 assert repr(d1) == "defaultdict(, {11: 41})" d2 = defaultdict(lambda: 0) # TODO: use 'int' when it's fixed... #self.assertEqual(d2.default_factory, int) d2[12] = 42 assert repr(d2) == "defaultdict(, {12: 42})" def foo(): return 43 d3 = defaultdict(foo) #self.assertTrue(d3.default_factory is foo) d3[13] assert repr(d3) == "defaultdict(, {13: 43})" # copy d1 = defaultdict(list) d2 = d1.copy() #self.assertEqual(type(d2), defaultdict) #self.assertEqual(d2.default_factory, None) assert d2 == {} #d1.default_factory = list #d3 = d1.copy() #self.assertEqual(type(d3), defaultdict) #self.assertEqual(d3.default_factory, list) #self.assertEqual(d3, {}) d1[42].append(0) #d4 = d1.copy() #assert d4 == {42: [0]} #d4[12] #assert d4 == {42: [], 12: []} # Issue 6637: Copy fails for empty default dict #d = defaultdict() #d['a'] = 42 #e = d.copy() #assert e['a'] == 42 # shallow copy foobar = list d1 = defaultdict(foobar) d1[1] += [1] d2 = copy(d1) #self.assertEqual(d2.default_factory, foobar) assert d2 == d1 #d1.default_factory = list d2 = copy(d1) #self.assertEqual(d2.default_factory, list) assert d2 == d1 # deep copy d1 = defaultdict(foobar) d1[1].append(1) d2 = deepcopy(d1) #self.assertEqual(d2.default_factory, foobar) assert d2 == d1 assert d1[1] is not d2[1] #d1.default_factory = list d2 = deepcopy(d1) #self.assertEqual(d2.default_factory, list) assert d2 == d1 # KeyError without factory #d1 = defaultdict() #try: # d1[(1,)] #except KeyError as err: # self.assertEqual(err.args[0], (1,)) #else: # self.fail("expected KeyError") # pickling #d = defaultdict(int) #d[1] #for proto in range(pickle.HIGHEST_PROTOCOL + 1): # s = pickle.dumps(d, proto) # o = pickle.loads(s) # self.assertEqual(d, o) # union i = defaultdict(int, {1: 1, 2: 2}) s = defaultdict(int, {0: 0, 1: 111}) i_s = i | s #self.assertIs(i_s.default_factory, int) assert i_s == {1: 111, 2: 2, 0: 0} assert sorted(i_s) == [0, 1, 2] s_i = s | i #self.assertIs(s_i.default_factory, str) assert s_i == {0: 0, 1: 1, 2: 2} assert sorted(s_i) == [0, 1, 2] i_ds = i | dict(s) #self.assertIs(i_ds.default_factory, int) assert i_ds == {1: 111, 2: 2, 0: 0} assert sorted(i_ds) == [0, 1, 2] ds_i = dict(s) | i #self.assertIs(ds_i.default_factory, int) assert ds_i == {0: 0, 1: 1, 2: 2} assert sorted(ds_i) == [0, 1, 2] # We inherit a fine |= from dict, so just a few sanity checks here: i |= list(s.items()) #self.assertIs(i.default_factory, int) assert i == {1: 111, 2: 2, 0: 0} assert sorted(i), [1, 2, 0] # general s = 'mississippi' d = defaultdict(int) for k in s: d[k] += 1 assert sorted(d.items()) == [('i', 4), ('m', 1), ('p', 2), ('s', 4)] s = 'mississippi' d = defaultdict(int) for k in s: d[k] = d.get(k, 0) + 1 assert sorted(d.items()) == [('i', 4), ('m', 1), ('p', 2), ('s', 4)] s = [('yellow', 1), ('blue', 2), ('yellow', 3), ('blue', 4), ('red', 1)] d = defaultdict(list) for k, v in s: d[k].append(v) assert sorted(d.items()) == [('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])] def constant_factory(value): return lambda: value d = defaultdict(constant_factory('')) assert d[10] == '' test_defaultdict()