diff options
Diffstat (limited to 'Lib/random.py')
| -rw-r--r-- | Lib/random.py | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/Lib/random.py b/Lib/random.py index 14ac5e5..4642928 100644 --- a/Lib/random.py +++ b/Lib/random.py @@ -41,7 +41,7 @@ from types import MethodType as _MethodType, BuiltinMethodType as _BuiltinMethod 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 os import urandom as _urandom -from collections.abc import Set as _Set, Sequence as _Sequence +from _collections_abc import Set as _Set, Sequence as _Sequence from hashlib import sha512 as _sha512 __all__ = ["Random","seed","random","uniform","randint","choice","sample", @@ -105,7 +105,9 @@ class Random(_random.Random): if a is None: try: - a = int.from_bytes(_urandom(32), 'big') + # Seed with enough bytes to span the 19937 bit + # state space for the Mersenne Twister + a = int.from_bytes(_urandom(2500), 'big') except NotImplementedError: import time a = int(time.time() * 256) # use fractional seconds @@ -151,6 +153,9 @@ class Random(_random.Random): ## -------------------- pickle support ------------------- + # Issue 17489: Since __reduce__ was defined to fix #759889 this is no + # longer called; we leave it here because it has been here since random was + # rewritten back in 2001 and why risk breaking something. def __getstate__(self): # for pickle return self.getstate() @@ -216,10 +221,11 @@ class Random(_random.Random): Method=_MethodType, BuiltinMethod=_BuiltinMethodType): "Return a random int in the range [0,n). Raises ValueError if n==0." + random = self.random getrandbits = self.getrandbits # Only call self.getrandbits if the original random() builtin method # has not been overridden or if a new getrandbits() was supplied. - if type(self.random) is BuiltinMethod or type(getrandbits) is Method: + if type(random) is BuiltinMethod or type(getrandbits) is Method: k = n.bit_length() # don't use (n-1) here because n can be 1 r = getrandbits(k) # 0 <= r < 2**k while r >= n: @@ -227,7 +233,6 @@ class Random(_random.Random): return r # There's an overriden random() method but no new getrandbits() method, # so we can only use random() from here. - random = self.random if n >= maxsize: _warn("Underlying random() generator does not supply \n" "enough bits to choose from a population range this large.\n" @@ -251,10 +256,11 @@ class Random(_random.Random): return seq[i] def shuffle(self, x, random=None): - """x, random=random.random -> shuffle list x in place; return None. + """Shuffle list x in place, and return None. - Optional arg random is a 0-argument function returning a random - float in [0.0, 1.0); by default, the standard random.random. + Optional argument random is a 0-argument function returning a + random float in [0.0, 1.0); if it is the default None, the + standard random.random will be used. """ @@ -349,7 +355,10 @@ class Random(_random.Random): """ u = self.random() - c = 0.5 if mode is None else (mode - low) / (high - low) + try: + c = 0.5 if mode is None else (mode - low) / (high - low) + except ZeroDivisionError: + return low if u > c: u = 1.0 - u c = 1.0 - c |