TicToc timing class 1st time an instance is called, it sets a timestamp (time.time()) 2nd time, it computes and returns the difference (in seconds, float).

tictoc.py

class TicToc(object):
    '''Timing class
    
    1st time an instance is called, it sets  a timestamp (time.time())
    2nd time, it computes and returns the difference (in seconds, float).
    
    Examples
    --------
    >>> t = TicToc()
    >>> t() # returns time.time()
    1389281072.45
    >>> time.sleep(0.1)
    >>> t()
    0.100247144699
    '''
    def __init__(self, fmt=None):
        from time import time
        self.time = time
        self.start = None
        self.fmt = fmt
    
    def __call__(self, *args):
        if self.start is None:
            return self.tic()
        else:
            return self.toc()
    
    def tic(self):
        t = self.time()
        self.start = t
        return t
    
    def toc(self):
        t2 = self.time()
        delta = t2 - self.start
        if self.fmt is not None:
            print(self.fmt.format(delta))
        # reset the TicToc:
        self.start = None
        return delta
if __name__ == '__main__':
    import time
    t = TicToc()
    print(t())
    time.sleep(0.1)
    print(t())
    
    # with printing
    t()
    t.fmt = 'simulation time: {:.2f} s'
    time.sleep(0.2)
    print(t())