Excellent, I'll see if I can implement that. I was thinking more base data-type, but that seems impossible in python.
17 iterations (rarghh!) But yeah, I'll try that, thanks. On Thu, Dec 1, 2011 at 5:38 AM, Ian Kelly <ian.g.ke...@gmail.com> wrote: > On Wed, Nov 30, 2011 at 9:26 AM, Alec Taylor <alec.tayl...@gmail.com> wrote: >> On Thu, Dec 1, 2011 at 3:18 AM, Ian Kelly <ian.g.ke...@gmail.com> wrote: >>> On Wed, Nov 30, 2011 at 8:19 AM, Alec Taylor <alec.tayl...@gmail.com> wrote: >>>> Good evening, >>>> >>>> I have defined a new numbering structure for certain mathematical >>>> advantages. >>>> >>>> How do I implement this in Python, or would I be better off writing >>>> this in C or C++? >>>> >>>> Ultra concise definition: http://i42.tinypic.com/af7w4h.png >>>> LaTeX source: http://pastebin.tlhiv.org/Kf6jPRkI >>>> >>>> Thanks for all suggestions, >>> >>> So if I am understanding your definition correctly your hexavigesimals >>> are ordered like this? >>> >>> 0, 1, ..., 9, A, B, ..., P, >>> >>> 0A, 0B, ..., 0P, >>> 1A, 1B, ..., 1P, >>> ..., >>> 9A, 9B, ..., 9P, >>> >>> A0, A1, ..., A9, >>> B0, B1, ..., B9, >>> ..., >>> P0, P1, ..., P9 >>> >>> And that's it, since your constraints preclude anything with more than 2 >>> digits? >> >> To put it simply: >> >> I want a hexavigesimal of length n where each element contains at >> least one letter {A, B, ..., P} and one number {0, 1, 2, ... }. >> (unless n is less than 2, in which case only one of those constraints >> need to be met) >> >> and I want addition only for incrementing the element. >> >> Why do I want all this I hear you ask? - For use as a >> unique-identifier. I want a unique-ID of size 3. (3 positions, i.e. >> P0A) >> >> Any suggestions on how to implement this in python would be appreciated. > > Okay, that's much clearer. If you don't actually care about the > ordinal value of each element, only about incrementing them, then I > suggest implementing increment as follows: > > 1. Convert the string to an int using the regular base-26 conversion > with the int() built-in. > 2. In a loop, add 1 to the value. > 3. Convert the value back to a string using the same base-26 > conversion. I don't know of a built-in that does this, so you'll need > to write your own, which isn't too difficult. > 4. Check whether the new string meets all your constraints. If it > does, return it. If not, go back to 2. and try again with the next > integer. > > At most it will take 17 iterations to find a valid value, but most of > the time the first value tried will be valid. > > I assume you're already aware that with 3 digits you'll only have > 12480 possible unique IDs using this scheme? It just doesn't seem > like very many to me. > > Cheers, > Ian -- http://mail.python.org/mailman/listinfo/python-list
