On Mon, Sep 25, 2017 at 03:34:05AM +0000, edmundo pierre via Tutor wrote: > I am trying to sort float numbers input by an user from the bigger to > smaller number. I do not know how to compare float numbers. Any ideas? > Thank you!
If the numbers are provided by the user, they will be in the form of strings, so you have to convert to float first: # pretend these came from the user a = '1.2' b = '100.9' c = '2.4' alist = [a, b, c] alist.sort() print(alist) will print the result: ['1.2', '100.9', '2.4'] which is not what you want. Instead, do this: # pretend these came from the user a = '1.2' b = '100.9' c = '2.4' alist = [float(a), float(b), float(c)] alist.sort() print(alist) which will print [1.2, 2.4, 100.9] instead. Also, you can make a copy of the list using sorted() instead of sort(): alist = [float(a), float(b), float(c)] print(sorted(alist)) Be warned: some numbers which can be written exactly in decimal, like 0.1, may sometimes appear ever-so-slightly "off" when you convert to a float. This is not a bug, but an unfortunate side-effect of the way computers do arithmetic in base 2 (binary). Feel free to ask if you would like more information. -- Steve _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
