diff options
| -rw-r--r-- | Lib/whrandom.py | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/Lib/whrandom.py b/Lib/whrandom.py index 7f33fd6..3bfd14f 100644 --- a/Lib/whrandom.py +++ b/Lib/whrandom.py @@ -86,14 +86,53 @@ class whrandom: return a + (b-a) * self.random() # # Get a random integer in the range [a, b] including both end points. + # (Deprecated; use randrange below.) # def randint(self, a, b): - return a + int(self.random() * (b+1-a)) + return self.randrange(a, b+1) # # Choose a random element from a non-empty sequence. # def choice(self, seq): return seq[int(self.random() * len(seq))] + # + # Choose a random item from range([start,] step[, stop]). + # This fixes the problem with randint() which includes the + # endpoint; in Python this is usually not what you want. + # + def randrange(self, start, stop=None, step=1, + # Do not supply the following arguments + int=int, default=None): + # 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()" + if stop is default: + if istart > 0: + return int(self.random() * istart) + raise ValueError, "empty range for randrange()" + istop = int(stop) + if istop != stop: + raise ValueError, "non-integer stop for randrange()" + if step == 1: + if istart < istop: + return istart + int(self.random() * + (istop - istart)) + raise ValueError, "empty range for randrange()" + istep = int(step) + if istep != step: + raise ValueError, "non-integer step for randrange()" + if istep > 0: + n = (istop - istart + istep - 1) / istep + elif istep < 0: + n = (istop - istart + istep + 1) / istep + else: + raise ValueError, "zero step for randrange()" + + if n <= 0: + raise ValueError, "empty range for randrange()" + return istart + istep*int(self.random() * n) # Initialize from the current time @@ -104,3 +143,4 @@ random = _inst.random uniform = _inst.uniform randint = _inst.randint choice = _inst.choice +randrange = _inst.randrange |