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Minor clean-up of function parameters in random().

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Raymond Hettinger 2013-10-05 21:52:06 -07:00
commit be74a3d721
1 changed files with 17 additions and 12 deletions
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29
Lib/random.py
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@ -165,18 +165,17 @@ class Random(_random.Random):
## -------------------- integer methods ------------------- ## -------------------- integer methods -------------------
def randrange(self, start, stop=None, step=1, int=int): def randrange(self, start, stop=None, step=1, _int=int):
"""Choose a random item from range(start, stop[, step]). """Choose a random item from range(start, stop[, step]).
This fixes the problem with randint() which includes the This fixes the problem with randint() which includes the
endpoint; in Python this is usually not what you want. endpoint; in Python this is usually not what you want.
Do not supply the 'int' argument.
""" """
# This code is a bit messy to make it fast for the # This code is a bit messy to make it fast for the
# common case while still doing adequate error checking. # common case while still doing adequate error checking.
istart = int(start) istart = _int(start)
if istart != start: if istart != start:
raise ValueError("non-integer arg 1 for randrange()") raise ValueError("non-integer arg 1 for randrange()")
if stop is None: if stop is None:
@ -185,7 +184,7 @@ class Random(_random.Random):
raise ValueError("empty range for randrange()") raise ValueError("empty range for randrange()")
# stop argument supplied. # stop argument supplied.
istop = int(stop) istop = _int(stop)
if istop != stop: if istop != stop:
raise ValueError("non-integer stop for randrange()") raise ValueError("non-integer stop for randrange()")
width = istop - istart width = istop - istart
@ -195,7 +194,7 @@ class Random(_random.Random):
raise ValueError("empty range for randrange() (%d,%d, %d)" % (istart, istop, width)) raise ValueError("empty range for randrange() (%d,%d, %d)" % (istart, istop, width))
# Non-unit step argument supplied. # Non-unit step argument supplied.
istep = int(step) istep = _int(step)
if istep != step: if istep != step:
raise ValueError("non-integer step for randrange()") raise ValueError("non-integer step for randrange()")
if istep > 0: if istep > 0:
@ -254,21 +253,27 @@ class Random(_random.Random):
raise IndexError('Cannot choose from an empty sequence') raise IndexError('Cannot choose from an empty sequence')
return seq[i] return seq[i]
def shuffle(self, x, random=None, int=int): def shuffle(self, x, random=None):
"""Shuffle list x in place, and return None. """Shuffle list x in place, and return None.
Optional argument random is a 0-argument function returning a Optional argument random is a 0-argument function returning a
random float in [0.0, 1.0); if it is the default None, the random float in [0.0, 1.0); if it is the default None, the
standard random.random will be used. standard random.random will be used.
Do not supply the 'int' argument.
""" """
randbelow = self._randbelow if random is None:
for i in reversed(range(1, len(x))): randbelow = self._randbelow
# pick an element in x[:i+1] with which to exchange x[i] for i in reversed(range(1, len(x))):
j = randbelow(i+1) if random is None else int(random() * (i+1)) # pick an element in x[:i+1] with which to exchange x[i]
x[i], x[j] = x[j], x[i] j = randbelow(i+1)
x[i], x[j] = x[j], x[i]
else:
_int = int
for i in reversed(range(1, len(x))):
# pick an element in x[:i+1] with which to exchange x[i]
j = _int(random() * (i+1))
x[i], x[j] = x[j], x[i]
def sample(self, population, k): def sample(self, population, k):
"""Chooses k unique random elements from a population sequence or set. """Chooses k unique random elements from a population sequence or set.