Hi all. I would like to post the very small py files I have written while doing this. Would anyone object. I think at most there be 20 lines of code all the files put together. I woul dlike to hear some crituqe on them Thanks
On Apr 4, 2005 11:08 AM, Christopher Smith <[EMAIL PROTECTED]> wrote: > > On Monday, Apr 4, 2005, at 05:01 America/Chicago, > [EMAIL PROTECTED] wrote: > > > Would I used an if else: construction to determine where the INR value > > lay and decide what precentage to increase it by? > > > > Yes, that seems to be the right way to do that. The caveat is that > when you are using boolean tests like "if INR < 1.15:" you are using > floating point numbers that *by definition* have limited ability to > represent the numbers you type. > > "1.15" is actually "1.1499999999999999", so calculation that "on paper" > would have led to a value of 1.15 will appear to be larger than the > floating point value of 1.15. When you are checking to see if your > program is running right and you find that a test like "if INR < 1.15" > doesn't work like you think it should this can lead to a lot of hair > pulling...until you remember the floating point issue. e.g. on paper, > a and b as shown below should be the same, but they aren't > > ### > >>> a=.23*5 # which equals 1.15 on paper > >>> b=1.15 > >>> a==b > False > >>> a > 1.1500000000000001 > >>> b > 1.1499999999999999 > ### > > If one cares about what side of the boundary values get evaluated to > then either exact numbers should be used (e.g. the new decimal type of > python 2.4) or else the tests should use the round function to get both > numbers to a compatible precision for comparison (e.g. use "if > round(INR,2) < round(1.15,2):" instead of "if INR < 1.15". > > It is instructive to see what the round function does to the a and b > used in the example above: > > ### > >>> a,b=round(.23*5,2),round(1.15,2) > >>> a==b > True > >>> a > 1.1499999999999999 > >>> b > 1.1499999999999999 > ### > > Both numbers are still floats, but they are floats that both best > represent, to 2 decimal places, their respective values. > > /c > > _______________________________________________ > Tutor maillist - Tutor@python.org > http://mail.python.org/mailman/listinfo/tutor > _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
