For a StopWatch helper class, here is my solution which gives you precision on output and also access to the raw start time:
class StopWatch:
def __init__(self):
self.start()
def start(self):
self._startTime = time.time()
def getStartTime(self):
return self._startTime
def elapsed(self, prec=3):
prec = 3 if prec is None or not isinstance(prec, (int, long)) else prec
diff= time.time() - self._startTime
return round(diff, prec)
def round(n, p=0):
m = 10 ** p
return math.floor(n * m + 0.5) / m