gistfile1.py

from time import time

class StopWatch():
    """
    Like using a stopwatch to time things, use start and stop methods,
    restart will reset the timer
    """

    def __init__(self, start=False):
        """New timers are not started by default
        """
        if not start:
            now = time()
            self._counter = 0.0
            self._start = now
            self._stop = now
        else:
            self.restart()

    def restart(self):
        """Reset timer to zero and start
        """
        self._counter = 0.0
        self._start = time()
        self._stop = None

    def _get_end(self):
        return self._stop if self._stop else time()

    @property
    def time(self):
        """Current elapsed time on the clock in seconds as a float
        """
        end = self._get_end()
        return end - self._start + self._counter

    def start(self):
        """Continue elapsed time
        """
        self._counter = self.time
        self._start = time()
        self._stop = None

    def stop(self):
        """Multiple calls to stop won't do anything
        """
        self._stop = self._get_end()

    def __str__(self):
        return str(self.time)