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Code Issues Projects Releases Packages Wiki Activity Actions 10

* Remove dependency on binascii.hexlify by using int.from_bytes().

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* Use the new super() with no arguments.
* Replace pow() call with the ** operator.
* Increase urandom seeding from 16 bytes to 32 bytes.
* Clean-up docstring.
This commit is contained in:
Raymond Hettinger 2010-09-08 18:48:21 +00:00
parent f69af1e959
commit 183cd1fae3
1 changed files with 9 additions and 10 deletions
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19
Lib/random.py
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@ -42,7 +42,6 @@ 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 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 sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin
from os import urandom as _urandom from os import urandom as _urandom
from binascii import hexlify as _hexlify
import collections as _collections import collections as _collections
__all__ = ["Random","seed","random","uniform","randint","choice","sample", __all__ = ["Random","seed","random","uniform","randint","choice","sample",
@ -97,16 +96,16 @@ class Random(_random.Random):
None or no argument seeds from current time or from an operating None or no argument seeds from current time or from an operating
system specific randomness source if available. system specific randomness source if available.
For version 2 (the default), all of the bits are used if a is a str, For version 2 (the default), all of the bits are used if *a *is a str,
bytes, or bytearray. For version 1, the hash() of a is used instead. bytes, or bytearray. For version 1, the hash() of *a* is used instead.
If a is an int, all bits are used. If *a* is an int, all bits are used.
""" """
if a is None: if a is None:
try: try:
a = int(_hexlify(_urandom(16)), 16) a = int.from_bytes(_urandom(32), 'big')
except NotImplementedError: except NotImplementedError:
import time import time
a = int(time.time() * 256) # use fractional seconds a = int(time.time() * 256) # use fractional seconds
@ -114,7 +113,7 @@ class Random(_random.Random):
if version == 2 and isinstance(a, (str, bytes, bytearray)): if version == 2 and isinstance(a, (str, bytes, bytearray)):
if isinstance(a, str): if isinstance(a, str):
a = a.encode("utf8") a = a.encode("utf8")
a = int(_hexlify(a), 16) a = int.from_bytes(a, 'big')
super().seed(a) super().seed(a)
self.gauss_next = None self.gauss_next = None
@ -139,7 +138,7 @@ class Random(_random.Random):
internalstate = tuple(x % (2**32) for x in internalstate) internalstate = tuple(x % (2**32) for x in internalstate)
except ValueError as e: except ValueError as e:
raise TypeError from e raise TypeError from e
super(Random, self).setstate(internalstate) super().setstate(internalstate)
else: else:
raise ValueError("state with version %s passed to " raise ValueError("state with version %s passed to "
"Random.setstate() of version %s" % "Random.setstate() of version %s" %
@ -613,7 +612,7 @@ class Random(_random.Random):
# Jain, pg. 499; bug fix courtesy Bill Arms # Jain, pg. 499; bug fix courtesy Bill Arms
u = 1.0 - self.random() u = 1.0 - self.random()
return alpha * pow(-_log(u), 1.0/beta) return alpha * (-_log(u)) ** (1.0/beta)
## --------------- Operating System Random Source ------------------ ## --------------- Operating System Random Source ------------------
@ -627,7 +626,7 @@ class SystemRandom(Random):
def random(self): def random(self):
"""Get the next random number in the range [0.0, 1.0).""" """Get the next random number in the range [0.0, 1.0)."""
return (int(_hexlify(_urandom(7)), 16) >> 3) * RECIP_BPF return (int.from_bytes(_urandom(7), 'big') >> 3) * RECIP_BPF
def getrandbits(self, k): def getrandbits(self, k):
"""getrandbits(k) -> x. Generates a long int with k random bits.""" """getrandbits(k) -> x. Generates a long int with k random bits."""
@ -636,7 +635,7 @@ class SystemRandom(Random):
if k != int(k): if k != int(k):
raise TypeError('number of bits should be an integer') raise TypeError('number of bits should be an integer')
bytes = (k + 7) // 8 # bits / 8 and rounded up bytes = (k + 7) // 8 # bits / 8 and rounded up
x = int(_hexlify(_urandom(bytes)), 16) x = int.from_bytes(_urandom(bytes), 'big')
return x >> (bytes * 8 - k) # trim excess bits return x >> (bytes * 8 - k) # trim excess bits
def seed(self, *args, **kwds): def seed(self, *args, **kwds):