[Python-checkins] Statistics internals: Make fewer calls to _coerce() when data types are mixed (GH-31619)
rhettinger
webhook-mailer at python.org
Mon Feb 28 12:44:02 EST 2022
https://github.com/python/cpython/commit/d5b7bba43b7d9559e9894d263ece337084dc4b8d
commit: d5b7bba43b7d9559e9894d263ece337084dc4b8d
branch: main
author: Raymond Hettinger <rhettinger at users.noreply.github.com>
committer: rhettinger <rhettinger at users.noreply.github.com>
date: 2022-02-28T11:43:52-06:00
summary:
Statistics internals: Make fewer calls to _coerce() when data types are mixed (GH-31619)
files:
M Lib/statistics.py
diff --git a/Lib/statistics.py b/Lib/statistics.py
index eef2453bc7394..f3bc9a1f34639 100644
--- a/Lib/statistics.py
+++ b/Lib/statistics.py
@@ -137,6 +137,7 @@
from itertools import groupby, repeat
from bisect import bisect_left, bisect_right
from math import hypot, sqrt, fabs, exp, erf, tau, log, fsum
+from functools import reduce
from operator import mul
from collections import Counter, namedtuple, defaultdict
@@ -183,11 +184,12 @@ def _sum(data):
allowed.
"""
count = 0
+ types = set()
+ types_add = types.add
partials = {}
partials_get = partials.get
- T = int
for typ, values in groupby(data, type):
- T = _coerce(T, typ) # or raise TypeError
+ types_add(typ)
for n, d in map(_exact_ratio, values):
count += 1
partials[d] = partials_get(d, 0) + n
@@ -199,6 +201,7 @@ def _sum(data):
else:
# Sum all the partial sums using builtin sum.
total = sum(Fraction(n, d) for d, n in partials.items())
+ T = reduce(_coerce, types, int) # or raise TypeError
return (T, total, count)
@@ -214,11 +217,12 @@ def _ss(data, c=None):
T, total, count = _sum((d := x - c) * d for x in data)
return (T, total, count)
count = 0
+ types = set()
+ types_add = types.add
sx_partials = defaultdict(int)
sxx_partials = defaultdict(int)
- T = int
for typ, values in groupby(data, type):
- T = _coerce(T, typ) # or raise TypeError
+ types_add(typ)
for n, d in map(_exact_ratio, values):
count += 1
sx_partials[d] += n
@@ -236,6 +240,7 @@ def _ss(data, c=None):
# This formula has poor numeric properties for floats,
# but with fractions it is exact.
total = (count * sxx - sx * sx) / count
+ T = reduce(_coerce, types, int) # or raise TypeError
return (T, total, count)
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