Re: Cant think of an elegant lua solution to this little problem

[Paul K <paulclinger@...>]

> The limitation of 12 characters can't be extended much, surely no more
> than 16 characters, I don't remember the actual limit for 'double'.
> padnum converts numbers to double and then back to string, so with
> numbers too big this won't work due to limited precision. E.g. padnum
> will turn "10000000000000001" and "10000000000000000" into the same
> number no matter what.

Agree; I just sent an improved version that shouldn't suffer from this problem.

Paul.

On Sat, Aug 25, 2012 at 5:23 PM, GrayFace <sergroj@mail.ru> wrote:
> On 26.08.2012 3:37, Paul K wrote:
>>
>>  I'm not sure if this is by coincidence or not (as it may be just
>>  treated as the same value, which means that the sort order will be
>>  arbitrarily picked between 012 and 12), but it should be easy to fix
>>  the logic if you want a specific order; just add the length:
>>
>>  function alphanumsort(o)
>>     local function padnum(d) return
>>  ("%012d"):format(d)..("%02d"):format(12-#d) end
>>     table.sort(o, function(a,b)
>>       return tostring(a):gsub("%d+",padnum)<
>> tostring(b):gsub("%d+",padnum) end)
>>     return o
>>  end
>>
>>  Use format(12-#d) if you want 012 before 12 or format(#d) if you want
>>  12 before 012 (this is assuming the length is 12 or less). I'll update
>>  the blog post to reflect this.
>>
>
> In case of "012b" vs "12a" the second one should be smaller. I'm pretty
> confident it's just the case of strings being the same otherwise when
> lexicographical order should kick in.
> The limitation of 12 characters can't be extended much, surely no more
> than 16 characters, I don't remember the actual limit for 'double'.
> padnum converts numbers to double and then back to string, so with
> numbers too big this won't work due to limited precision. E.g. padnum
> will turn "10000000000000001" and "10000000000000000" into the same
> number no matter what.
>
> --
> Best regards,
> Sergey Rozhenko                 mailto:sergroj@mail.ru
>
>