[Tutor] RE: Base converter bases 2-62

[cino hilliard]

>From: "Jeff Shannon" <jeff@ccvcorp.com>
>To: tutor@python.org
>Subject: Re: [Tutor] RE: Base converter bases 2-62
>Date: Fri, 20 Jun 2003 12:39:38 -0700
>
>cino hilliard wrote:
>
>>>(Of course, as Magnus pointed out, this whole loop can be easily replaced 
>>>with 'dec = int(num, r1)' as long as you can cope with a maximum base of 
>>>32....
>>
>>Why even mention this? I went to all this trouble for base 32 max? the 
>>atol and ltoa in c do this
>>for you to base 36.
>>
>
>Whoops, I *meant* base 36, which is the documented maximum radix for int(). 
>  Python (and I believe the C library functions) don't
That is correct. The macro
#define b2b(b1,b2,num) itoa(strtol(num,NULL,b1),num,b2)
was one of my better acheivements to get a very short c program to convert 
base to base.
Of course no quotes here because of the powerful c parser and typing. 
Caveat:The integer cannot
exceed 2^31-1 So C won't process b2b(29,10,JEFFSHANNON) properly because 
JEFFSHANNON overflows integer.


>distinguish between upper and lower case for these conversions, which means 
>that there's 26 alpha + 10 numeric symbols available.  It's certainly 
>possible to use a wider range of symbols, but
Yes. That is the issue - getting python to do it because of the arbitrary 
integer precision.
>probably not of any practical value.

When 64 bit 128 bit and higher processor chips hit the mainstream you may 
change your opinion
if you want to get a base 64 representation. My convert.base would do this 
quickly if we used
the { and | as the value for 62 and 62 base 10.

>
>Jeff Shannon
>Technician/Programmer
>Credit International
>
>
>
>_______________________________________________
>Tutor maillist  -  Tutor@python.org
>http://mail.python.org/mailman/listinfo/tutor


  3         3        3         3        3        6            2              
  (0^0)
2   +  13  +  33  +  43  =  49   =  7    =  343   = 117649

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