Johnny Lee wrote: <snip> > Why are there so many nonsense tails? thanks for your help.
I guess you were expecting 0.039? You first need to understand floating point numbers: http://docs.python.org/tut/node16.html What you see are the effects of representation errors. The solution is presented here: http://www.python.org/peps/pep-0327.html But briefly, it means your code should read: from decimal import * t1 = "1130748744" t2 = "461" t3 = "1130748744" t4 = "500" time1 = t1+"."+t2 time2 = t3+"."+t4 print time1, time2 Decimal(time2) - Decimal(time1) -- http://mail.python.org/mailman/listinfo/python-list