https://github.com/python/cpython/commit/d5b7bba43b7d9559e9894d263ece337084d... commit: d5b7bba43b7d9559e9894d263ece337084dc4b8d branch: main author: Raymond Hettinger <rhettinger@users.noreply.github.com> committer: rhettinger <rhettinger@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)