diff --git a/Lib/random.py b/Lib/random.py index 73831c00f6..f8735d42a1 100644 --- a/Lib/random.py +++ b/Lib/random.py @@ -48,7 +48,7 @@ General notes on the underlying Mersenne Twister core generator: from warnings import warn as _warn from math import log as _log, exp as _exp, pi as _pi, e as _e, ceil as _ceil from math import sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin -from math import tau as TWOPI, floor as _floor +from math import tau as TWOPI, floor as _floor, isfinite as _isfinite try: from os import urandom as _urandom except ImportError: @@ -59,6 +59,7 @@ except ImportError: raise NotImplementedError("urandom") _os = None from _collections_abc import Set as _Set, Sequence as _Sequence +from operator import index as _index from itertools import accumulate as _accumulate, repeat as _repeat from bisect import bisect as _bisect try: @@ -109,6 +110,7 @@ LOG4 = _log(4.0) SG_MAGICCONST = 1.0 + _log(4.5) BPF = 53 # Number of bits in a float RECIP_BPF = 2 ** -BPF +_ONE = 1 class Random(_random.Random): @@ -300,7 +302,7 @@ class Random(_random.Random): ## -------------------- integer methods ------------------- - def randrange(self, start, stop=None, step=1): + def randrange(self, start, stop=None, step=_ONE): """Choose a random item from range(start, stop[, step]). This fixes the problem with randint() which includes the @@ -310,38 +312,68 @@ class Random(_random.Random): # This code is a bit messy to make it fast for the # common case while still doing adequate error checking. - istart = int(start) - if istart != start: - raise ValueError("non-integer arg 1 for randrange()") + try: + istart = _index(start) + except TypeError: + istart = int(start) + if istart != start: + _warn('randrange() will raise TypeError in the future', + DeprecationWarning, 2) + raise ValueError("non-integer arg 1 for randrange()") + _warn('non-integer arguments to randrange() have been deprecated ' + 'since Python 3.10 and will be removed in a subsequent ' + 'version', + DeprecationWarning, 2) if stop is None: + # We don't check for "step != 1" because it hasn't been + # type checked and converted to an integer yet. + if step is not _ONE: + raise TypeError('Missing a non-None stop argument') if istart > 0: return self._randbelow(istart) raise ValueError("empty range for randrange()") # stop argument supplied. - istop = int(stop) - if istop != stop: - raise ValueError("non-integer stop for randrange()") + try: + istop = _index(stop) + except TypeError: + istop = int(stop) + if istop != stop: + _warn('randrange() will raise TypeError in the future', + DeprecationWarning, 2) + raise ValueError("non-integer stop for randrange()") + _warn('non-integer arguments to randrange() have been deprecated ' + 'since Python 3.10 and will be removed in a subsequent ' + 'version', + DeprecationWarning, 2) width = istop - istart - if step == 1 and width > 0: - return istart + self._randbelow(width) - if step == 1: + try: + istep = _index(step) + except TypeError: + istep = int(step) + if istep != step: + _warn('randrange() will raise TypeError in the future', + DeprecationWarning, 2) + raise ValueError("non-integer step for randrange()") + _warn('non-integer arguments to randrange() have been deprecated ' + 'since Python 3.10 and will be removed in a subsequent ' + 'version', + DeprecationWarning, 2) + # Fast path. + if istep == 1: + if width > 0: + return istart + self._randbelow(width) raise ValueError("empty range for randrange() (%d, %d, %d)" % (istart, istop, width)) # Non-unit step argument supplied. - istep = int(step) - if istep != step: - raise ValueError("non-integer step for randrange()") if istep > 0: n = (width + istep - 1) // istep elif istep < 0: n = (width + istep + 1) // istep else: raise ValueError("zero step for randrange()") - if n <= 0: raise ValueError("empty range for randrange()") - return istart + istep * self._randbelow(n) def randint(self, a, b): @@ -437,13 +469,14 @@ class Random(_random.Random): # too many calls to _randbelow(), making them slower and # causing them to eat more entropy than necessary. - if isinstance(population, _Set): - _warn('Sampling from a set deprecated\n' - 'since Python 3.9 and will be removed in a subsequent version.', - DeprecationWarning, 2) - population = tuple(population) if not isinstance(population, _Sequence): - raise TypeError("Population must be a sequence. For dicts or sets, use sorted(d).") + if isinstance(population, _Set): + _warn('Sampling from a set deprecated\n' + 'since Python 3.9 and will be removed in a subsequent version.', + DeprecationWarning, 2) + population = tuple(population) + else: + raise TypeError("Population must be a sequence. For dicts or sets, use sorted(d).") n = len(population) if counts is not None: cum_counts = list(_accumulate(counts)) @@ -513,6 +546,8 @@ class Random(_random.Random): total = cum_weights[-1] + 0.0 # convert to float if total <= 0.0: raise ValueError('Total of weights must be greater than zero') + if not _isfinite(total): + raise ValueError('Total of weights must be finite') bisect = _bisect hi = n - 1 return [population[bisect(cum_weights, random() * total, 0, hi)] @@ -703,7 +738,7 @@ class Random(_random.Random): bbb = alpha - LOG4 ccc = alpha + ainv - while 1: + while True: u1 = random() if not 1e-7 < u1 < 0.9999999: continue @@ -770,7 +805,7 @@ class Random(_random.Random): # Jain, pg. 495 u = 1.0 - self.random() - return 1.0 / u ** (1.0 / alpha) + return u ** (-1.0 / alpha) def weibullvariate(self, alpha, beta): """Weibull distribution. @@ -866,7 +901,7 @@ def _test_generator(n, func, args): from time import perf_counter t0 = perf_counter() - data = [func(*args) for i in range(n)] + data = [func(*args) for i in _repeat(None, n)] t1 = perf_counter() xbar = mean(data)