"number-in-base" ``oneliner''

[Bengt Richter]

On Sat, 30 Oct 2004 09:02:14 GMT, bokr at oz.net (Bengt Richter) wrote:

>On Sat, 30 Oct 2004 07:48:34 GMT, bokr at oz.net (Bengt Richter) wrote:
>
>>On Sat, 30 Oct 2004 06:07:23 GMT, bokr at oz.net (Bengt Richter) wrote:
>>[...]
>>>Maybe something useful in this? Not very tested (and not terribly clear either ;-)
>>>
>>> >>> def number_in_base(x, N, digits):
>>> ...     return x==0 and digits[0] or '-'[:x<0] + ''.join([d for d in iter(
>>> ...                 lambda qr=[abs(x),0]:qr[0] and (
>>> ...                     qr.__setslice__(0,2,divmod(qr[0],N)) or digits[qr[1]])
>>> ...                 , 0)][::-1])
>>> ...
>>
>>Alternatively, a little more compactly (though I feel guilty about the -1 ;-):
>>
>> >>> def number_in_base(x, N=10, digits='0123456789ABCDEF'):
>> ...     return '-'[:x<0] + ''.join(list(iter(lambda qr=[abs(x),-1]: (qr[0] or qr[1]<0) and (
>> ...         qr.__setslice__(0,2,divmod(qr[0],N)) or digits[qr[1]]), False))[::-1])
>> ...
>
>Yet another, prefixing digits instead of joining reversed list:
>
> >>> def number_in_base(x, N=10, digits='0123456789ABCDEF'):
> ...     return '-'[:x<0]+reduce(lambda s,c:c+s, iter(lambda qr=[abs(x),-1]: (qr[0] or qr[1]<0)
> ...         and (qr.__setslice__(0,2,divmod(qr[0],N)) or digits[qr[1]]), False))
> ...

My best shot so far (unless I goofed ;-):

 >>> def number_in_base(x, N=10, digits='0123456789ABCDEF'):
 ...     return '-'[:x<0]+''.join([digits[r] for x in [[abs(x)]]
 ...         for x[0],r in iter(lambda:divmod(x[0], N), (0,0))][::-1]) or '0'
 ...
 >>> number_in_base( 126, 2)
 '1111110'
 >>> number_in_base(-126, 2)
 '-1111110'
 >>> number_in_base(-126, 8)
 '-176'
 >>> number_in_base(-126,16)
 '-7E'
 >>> number_in_base(   1,16)
 '1'
 >>> number_in_base(   1, 2)
 '1'
 >>> number_in_base(   0, 2)
 '0'

Regards,
Bengt Richter