On Apr 22, 11:09 am, Paul McGuire <[EMAIL PROTECTED]> wrote: > I am doing some simple timing of some elements of Python scripts, and > the simplest is to just call time.time() before and after key elements > of the script: > > t1 = time.time() > > # do lengthy operation > > t2 = time.time() > print "That took %f seconds" % (t2-t1)
Why would you do %f and not %.3f ? > > Unfortunately, this gives very ugly timing output, as just a floating > point number of seconds. After several iterations of writing a > formatter (strftime is not straightforward to use - it omits > milliseconds for one thing), I came up with this: > > def secondsToStr(t): > rediv = lambda ll,b : list(divmod(ll[0],b)) + ll[1:] > return "%d:%02d:%02d.%03d" % tuple(reduce(rediv,[[t*1000,], > 1000,60,60])) > > Now I can write: > > print "That took", secondsToStr(t2-t1),"seconds" > > and get nicely-formatted 0:00:12.345 style output. and it it runs for (say) 83+ seconds you will get "That took 0:01:23.456 seconds" which is ludicrous. And if you want to calculate a percentage speed-up later you will have to convert back to seconds. > > (I also posted this to the Python Cookbook.) > > -- Paul IMHO if your job is short, print "That took %.3f seconds" % (t2 - t1) is adequate, and your leading 0:00: is useless. If it runs for minutes or hours, then minutes or hours to (say) 4 significant digits is more than adequate, and printing milliseconds is useless. -- http://mail.python.org/mailman/listinfo/python-list
