Hello Richard! On Thursday July 1 2010 15:11:21 Richard D. Moores wrote: > Thanks to yours and others responses, I've learned some things I > didn't know, but remember, I'm starting with long ints such as
Also note that in Python 3 the "/" (division) operator returns a floating point number when you divide integers. This is one of the changes that Python 3 introduces. As you are using long integers (and you were previously writing about prime numbers) the precision of floating point numbers might not be enough for your purposes. Therefore you should probably use the integer division operator: "//" The following (edited) snippet from IPython demonstrates "//" and the loss of precision when using "/": ... Python 2.6.2 (r262:71600, Mar 29 2010, 15:30:01) Type "copyright", "credits" or "license" for more information. IPython 0.10 -- An enhanced Interactive Python. ... In [1]: from __future__ import division In [2]: a = 1000000000000000000000000000000000000000000000000000000002 In [3]: a Out[3]: 1000000000000000000000000000000000000000000000000000000002L In [4]: a//2 Out[4]: 500000000000000000000000000000000000000000000000000000001L In [5]: a/2 Out[5]: 4.9999999999999994e+56 In [6]: long(a/2) Out[6]: 499999999999999937061060126016582882140297920412594995200L Eike. _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor