On Thu, Mar 27, 2014 at 1:02 AM, Antoon Pardon <antoon.par...@rece.vub.ac.be> wrote: > There is a difference between how people say things and what is useful. > I remember when I was studying logarithms, a negative number like -5.73 > was written down as ̅6.27 (with a bar only over the six). That notation > had the advantage that the part after the decimal point stayed the same > if you added or subtracted whole numbers. Even if that would change the > sign.
That's highly significant with logs, especially when you're working with base 10 logs. >>> math.log10(1234) 3.091315159697223 >>> math.log10(12340) 4.091315159697223 >>> math.log10(123400) 5.091315159697223 >>> math.log10(1234000) 6.091315159697223 >>> math.log10(12.34) 1.0913151596972228 >>> math.log10(1.234) 0.09131515969722287 >>> math.log10(.1234) -0.9086848403027772 >>> math.log10(.01234) -1.9086848403027772 By showing those last ones as 1̅.091... and 2̅.091..., you emphasize the floating-point nature of the data: everything after the decimal is the mantissa, and everything before the decimal is the exponent. I can't say for sure as I don't really use that, but I can imagine that there might be something similar with dates and times - it's three days ago at 2:51, not two days and 21:09 ago. Or maybe it's just "print it out in a way that more closely matches the internal representation, to simplify debugging" :) ChrisA -- https://mail.python.org/mailman/listinfo/python-list
