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Automated merge with ssh://hg.python.org/cpython

This commit is contained in:
Steven D'Aprano 2016-05-05 04:47:10 +10:00
parent fcce462e9c 3b06e24352
commit 045e635100
2 changed files with 44 additions and 55 deletions
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68
Lib/statistics.py
View File

@ -105,6 +105,7 @@ import math
from fractions import Fraction
from decimal import Decimal
from itertools import groupby
from bisect import bisect_left, bisect_right
@ -223,56 +224,26 @@ def _exact_ratio(x):
# Optimise the common case of floats. We expect that the most often
# used numeric type will be builtin floats, so try to make this as
# fast as possible.
if type(x) is float:
if type(x) is float or type(x) is Decimal:
return x.as_integer_ratio()
try:
# x may be an int, Fraction, or Integral ABC.
return (x.numerator, x.denominator)
except AttributeError:
try:
# x may be a float subclass.
# x may be a float or Decimal subclass.
return x.as_integer_ratio()
except AttributeError:
try:
# x may be a Decimal.
return _decimal_to_ratio(x)
except AttributeError:
# Just give up?
pass
# Just give up?
pass
except (OverflowError, ValueError):
# float NAN or INF.
assert not math.isfinite(x)
assert not _isfinite(x)
return (x, None)
msg = "can't convert type '{}' to numerator/denominator"
raise TypeError(msg.format(type(x).__name__))
# FIXME This is faster than Fraction.from_decimal, but still too slow.
def _decimal_to_ratio(d):
"""Convert Decimal d to exact integer ratio (numerator, denominator).
>>> from decimal import Decimal
>>> _decimal_to_ratio(Decimal("2.6"))
(26, 10)
"""
sign, digits, exp = d.as_tuple()
if exp in ('F', 'n', 'N'): # INF, NAN, sNAN
assert not d.is_finite()
return (d, None)
num = 0
for digit in digits:
num = num*10 + digit
if exp < 0:
den = 10**-exp
else:
num *= 10**exp
den = 1
if sign:
num = -num
return (num, den)
def _convert(value, T):
"""Convert value to given numeric type T."""
if type(value) is T:
@ -305,6 +276,21 @@ def _counts(data):
return table
def _find_lteq(a, x):
'Locate the leftmost value exactly equal to x'
i = bisect_left(a, x)
if i != len(a) and a[i] == x:
return i
raise ValueError
def _find_rteq(a, l, x):
'Locate the rightmost value exactly equal to x'
i = bisect_right(a, x, lo=l)
if i != (len(a)+1) and a[i-1] == x:
return i-1
raise ValueError
# === Measures of central tendency (averages) ===
def mean(data):
@ -442,9 +428,15 @@ def median_grouped(data, interval=1):
except TypeError:
# Mixed type. For now we just coerce to float.
L = float(x) - float(interval)/2
cf = data.index(x) # Number of values below the median interval.
# FIXME The following line could be more efficient for big lists.
f = data.count(x) # Number of data points in the median interval.
# Uses bisection search to search for x in data with log(n) time complexity
# Find the position of leftmost occurence of x in data
l1 = _find_lteq(data, x)
# Find the position of rightmost occurence of x in data[l1...len(data)]
# Assuming always l1 <= l2
l2 = _find_rteq(data, l1, x)
cf = l1
f = l2 - l1 + 1
return L + interval*(n/2 - cf)/f

31
Lib/test/test_statistics.py
View File

@ -699,13 +699,12 @@ class ExactRatioTest(unittest.TestCase):
num, den = statistics._exact_ratio(x)
self.assertEqual(x, num/den)
@unittest.skipIf(True, "temporarily disabled: see #25928")
def test_decimal(self):
D = Decimal
_exact_ratio = statistics._exact_ratio
self.assertEqual(_exact_ratio(D("0.125")), (125, 1000))
self.assertEqual(_exact_ratio(D("12.345")), (12345, 1000))
self.assertEqual(_exact_ratio(D("-1.98")), (-198, 100))
self.assertEqual(_exact_ratio(D("0.125")), (1, 8))
self.assertEqual(_exact_ratio(D("12.345")), (2469, 200))
self.assertEqual(_exact_ratio(D("-1.98")), (-99, 50))
def test_inf(self):
INF = float("INF")
@ -731,7 +730,6 @@ class ExactRatioTest(unittest.TestCase):
self.assertIs(ratio[1], None)
self.assertEqual(type(ratio[0]), type(nan))
@unittest.skipIf(True, "temporarily disabled: see #25928")
def test_decimal_nan(self):
NAN = Decimal("NAN")
sNAN = Decimal("sNAN")
@ -745,18 +743,18 @@ class ExactRatioTest(unittest.TestCase):
class DecimalToRatioTest(unittest.TestCase):
# Test _decimal_to_ratio private function.
# Test _exact_ratio private function.
def test_infinity(self):
# Test that INFs are handled correctly.
inf = Decimal('INF')
self.assertEqual(statistics._decimal_to_ratio(inf), (inf, None))
self.assertEqual(statistics._decimal_to_ratio(-inf), (-inf, None))
self.assertEqual(statistics._exact_ratio(inf), (inf, None))
self.assertEqual(statistics._exact_ratio(-inf), (-inf, None))
def test_nan(self):
# Test that NANs are handled correctly.
for nan in (Decimal('NAN'), Decimal('sNAN')):
num, den = statistics._decimal_to_ratio(nan)
num, den = statistics._exact_ratio(nan)
# Because NANs always compare non-equal, we cannot use assertEqual.
# Nor can we use an identity test, as we don't guarantee anything
# about the object identity.
@ -769,30 +767,30 @@ class DecimalToRatioTest(unittest.TestCase):
for d in numbers:
# First test positive decimals.
assert d > 0
num, den = statistics._decimal_to_ratio(d)
num, den = statistics._exact_ratio(d)
self.assertGreaterEqual(num, 0)
self.assertGreater(den, 0)
# Then test negative decimals.
num, den = statistics._decimal_to_ratio(-d)
num, den = statistics._exact_ratio(-d)
self.assertLessEqual(num, 0)
self.assertGreater(den, 0)
def test_negative_exponent(self):
# Test result when the exponent is negative.
t = statistics._decimal_to_ratio(Decimal("0.1234"))
self.assertEqual(t, (1234, 10000))
t = statistics._exact_ratio(Decimal("0.1234"))
self.assertEqual(t, (617, 5000))
def test_positive_exponent(self):
# Test results when the exponent is positive.
t = statistics._decimal_to_ratio(Decimal("1.234e7"))
t = statistics._exact_ratio(Decimal("1.234e7"))
self.assertEqual(t, (12340000, 1))
def test_regression_20536(self):
# Regression test for issue 20536.
# See http://bugs.python.org/issue20536
t = statistics._decimal_to_ratio(Decimal("1e2"))
t = statistics._exact_ratio(Decimal("1e2"))
self.assertEqual(t, (100, 1))
t = statistics._decimal_to_ratio(Decimal("1.47e5"))
t = statistics._exact_ratio(Decimal("1.47e5"))
self.assertEqual(t, (147000, 1))
@ -1260,7 +1258,6 @@ class SumSpecialValues(NumericTestCase):
with decimal.localcontext(decimal.BasicContext):
self.assertRaises(decimal.InvalidOperation, statistics._sum, data)
@unittest.skipIf(True, "temporarily disabled: see #25928")
def test_decimal_snan_raises(self):
# Adding sNAN should raise InvalidOperation.
sNAN = Decimal('sNAN')