None of these answers work for me. The following code should work for python collections, classes, dataclasses, and namedtuples. I might have forgotten something, but so far this works for me.
import unittest
from collections import namedtuple, OrderedDict
from dataclasses import dataclass
from typing import Any
def are_almost_equal(o1: Any, o2: Any, max_abs_ratio_diff: float, max_abs_diff: float) -> bool:
"""
Compares two objects by recursively walking them trough. Equality is as usual except for floats.
Floats are compared according to the two measures defined below.
:param o1: The first object.
:param o2: The second object.
:param max_abs_ratio_diff: The maximum allowed absolute value of the difference.
`abs(1 - (o1 / o2)` and vice-versa if o2 == 0.0. Ignored if < 0.
:param max_abs_diff: The maximum allowed absolute difference `abs(o1 - o2)`. Ignored if < 0.
:return: Whether the two objects are almost equal.
"""
if type(o1) != type(o2):
return False
composite_type_passed = False
if hasattr(o1, '__slots__'):
if len(o1.__slots__) != len(o2.__slots__):
return False
if any(not are_almost_equal(getattr(o1, s1), getattr(o2, s2),
max_abs_ratio_diff, max_abs_diff)
for s1, s2 in zip(sorted(o1.__slots__), sorted(o2.__slots__))):
return False
else:
composite_type_passed = True
if hasattr(o1, '__dict__'):
if len(o1.__dict__) != len(o2.__dict__):
return False
if any(not are_almost_equal(k1, k2, max_abs_ratio_diff, max_abs_diff)
or not are_almost_equal(v1, v2, max_abs_ratio_diff, max_abs_diff)
for ((k1, v1), (k2, v2))
in zip(sorted(o1.__dict__.items()), sorted(o2.__dict__.items()))
if not k1.startswith('__')): # avoid infinite loops
return False
else:
composite_type_passed = True
if isinstance(o1, dict):
if len(o1) != len(o2):
return False
if any(not are_almost_equal(k1, k2, max_abs_ratio_diff, max_abs_diff)
or not are_almost_equal(v1, v2, max_abs_ratio_diff, max_abs_diff)
for ((k1, v1), (k2, v2)) in zip(sorted(o1.items()), sorted(o2.items()))):
return False
elif any(issubclass(o1.__class__, c) for c in (list, tuple, set)):
if len(o1) != len(o2):
return False
if any(not are_almost_equal(v1, v2, max_abs_ratio_diff, max_abs_diff)
for v1, v2 in zip(o1, o2)):
return False
elif isinstance(o1, float):
if o1 == o2:
return True
else:
if max_abs_ratio_diff > 0: # if max_abs_ratio_diff < 0, max_abs_ratio_diff is ignored
if o2 != 0:
if abs(1.0 - (o1 / o2)) > max_abs_ratio_diff:
return False
else: # if both == 0, we already returned True
if abs(1.0 - (o2 / o1)) > max_abs_ratio_diff:
return False
if 0 < max_abs_diff < abs(o1 - o2): # if max_abs_diff < 0, max_abs_diff is ignored
return False
return True
else:
if not composite_type_passed:
return o1 == o2
return True
class EqualityTest(unittest.TestCase):
def test_floats(self) -> None:
o1 = ('hi', 3, 3.4)
o2 = ('hi', 3, 3.400001)
self.assertTrue(are_almost_equal(o1, o2, 0.0001, 0.0001))
self.assertFalse(are_almost_equal(o1, o2, 0.00000001, 0.00000001))
def test_ratio_only(self):
o1 = ['hey', 10000, 123.12]
o2 = ['hey', 10000, 123.80]
self.assertTrue(are_almost_equal(o1, o2, 0.01, -1))
self.assertFalse(are_almost_equal(o1, o2, 0.001, -1))
def test_diff_only(self):
o1 = ['hey', 10000, 1234567890.12]
o2 = ['hey', 10000, 1234567890.80]
self.assertTrue(are_almost_equal(o1, o2, -1, 1))
self.assertFalse(are_almost_equal(o1, o2, -1, 0.1))
def test_both_ignored(self):
o1 = ['hey', 10000, 1234567890.12]
o2 = ['hey', 10000, 0.80]
o3 = ['hi', 10000, 0.80]
self.assertTrue(are_almost_equal(o1, o2, -1, -1))
self.assertFalse(are_almost_equal(o1, o3, -1, -1))
def test_different_lengths(self):
o1 = ['hey', 1234567890.12, 10000]
o2 = ['hey', 1234567890.80]
self.assertFalse(are_almost_equal(o1, o2, 1, 1))
def test_classes(self):
class A:
d = 12.3
def __init__(self, a, b, c):
self.a = a
self.b = b
self.c = c
o1 = A(2.34, 'str', {1: 'hey', 345.23: [123, 'hi', 890.12]})
o2 = A(2.34, 'str', {1: 'hey', 345.231: [123, 'hi', 890.121]})
self.assertTrue(are_almost_equal(o1, o2, 0.1, 0.1))
self.assertFalse(are_almost_equal(o1, o2, 0.0001, 0.0001))
o2.hello = 'hello'
self.assertFalse(are_almost_equal(o1, o2, -1, -1))
def test_namedtuples(self):
B = namedtuple('B', ['x', 'y'])
o1 = B(3.3, 4.4)
o2 = B(3.4, 4.5)
self.assertTrue(are_almost_equal(o1, o2, 0.2, 0.2))
self.assertFalse(are_almost_equal(o1, o2, 0.001, 0.001))
def test_classes_with_slots(self):
class C(object):
__slots__ = ['a', 'b']
def __init__(self, a, b):
self.a = a
self.b = b
o1 = C(3.3, 4.4)
o2 = C(3.4, 4.5)
self.assertTrue(are_almost_equal(o1, o2, 0.3, 0.3))
self.assertFalse(are_almost_equal(o1, o2, -1, 0.01))
def test_dataclasses(self):
@dataclass
class D:
s: str
i: int
f: float
@dataclass
class E:
f2: float
f4: str
d: D
o1 = E(12.3, 'hi', D('hello', 34, 20.01))
o2 = E(12.1, 'hi', D('hello', 34, 20.0))
self.assertTrue(are_almost_equal(o1, o2, -1, 0.4))
self.assertFalse(are_almost_equal(o1, o2, -1, 0.001))
o3 = E(12.1, 'hi', D('ciao', 34, 20.0))
self.assertFalse(are_almost_equal(o2, o3, -1, -1))
def test_ordereddict(self):
o1 = OrderedDict({1: 'hey', 345.23: [123, 'hi', 890.12]})
o2 = OrderedDict({1: 'hey', 345.23: [123, 'hi', 890.0]})
self.assertTrue(are_almost_equal(o1, o2, 0.01, -1))
self.assertFalse(are_almost_equal(o1, o2, 0.0001, -1))
