[Python-Dev] str with base

Tue Jan 17 05:49:26 CET 2006

On Jan 16, 2006, at 8:18 PM, Barry Warsaw wrote:
> On Tue, 2006年01月17日 at 15:08 +1100, Andrew Bennetts wrote:
>>> My reaction having read this far was "huh?". It took some time 
>> (several
>> seconds) before it occurred to me what you wanted str(5,2) to 
>> mean, and why it
>> should give '101'.
>>>> If you'd proposed, say (5).as_binary() == '101', or "5".encode 
>> ("base2"), I
>> wouldn't have been as baffled. Or perhaps even str(5, base=2), 
>> but frankly the
>> idea of the string type doing numeric base conversions seems weird 
>> to me, rather
>> than symmetric.
>>>> I wouldn't mind seeing arbitrary base encoding of integers 
>> included somewhere,
>> but as a method of str -- let alone the constructor! -- it feels 
>> quite wrong.
>> Hear, hear. I was similarly perplexed when I first read that!

The only bases I've ever really had a good use for are 2, 8, 10, and 
16. There are currently formatting codes for 8 (o), 10 (d, u), and 
16 (x, X). Why not just add a string format code for unsigned 
binary? The obvious choice is probably "b".
For example:
 >>> '%08b' % (12)
'00001100'
 >>> '%b' % (12)
'1100'
I'd probably expect "5".encode("base2") to return '00110101', because 
"5".encode("hex") returns '35'
-bob