[Python-Dev] str with base

[Bob Ippolito]

On Jan 19, 2006, at 11:12 AM, Guido van Rossum wrote:

> On 1/19/06, Fredrik Lundh <fredrik at pythonware.com> wrote:
>> Guido van Rossum wrote:
>>
>>> I think we ought to let this sit for a while and come back to it  
>>> in a
>>> few week's time. Is 'base' really the right name? It could just as
>>> well be considered a conversion in the other direction.
>>
>> the same applies to hex and oct, of course.
>
> Right. And this is not a hypothetical issue either -- in Perl, hex and
> oct *do* work the other way I believe. More reasons to get rid of
> these in Python 3000. Perhaps we should also get rid of hex/oct
> lterals?

In Perl, hex(n) is like int(n, 16) and oct(n) is like int(n, 8) --  
but they "try very hard" to make sense out of the given scalar (e.g.  
more like int(n, 0) with a suggestion for base).

$ perl -e 'print hex("12") . " " . oct("12") . " " . oct("0x12") . "  
" . hex("fubar")'
18 10 18 15

If you notice, oct("0x12") gives the hexadecimal result, and the  
functions will try and make a value even out of garbage data.

In Ruby, you have the optional radix argument to_s and to_i, where  
to_i will just return 0 for invalid values.  They will take any radix  
from 2..36.

$ irb
irb(main):001:0> 12.to_s
=> "12"
irb(main):002:0> 12.to_s(16)
=> "c"
irb(main):003:0> 12.to_s(8)
=> "14"
irb(main):004:0> "12".to_i(8)
=> 10
irb(main):005:0> "12".to_i(16)
=> 18
irb(main):006:0> "0x12".to_i(16)
=> 18
irb(main):007:0> "0x12".to_i(8)
=> 0
irb(main):008:0> "0x12".to_i
=> 0
irb(main):009:0> "fubar".to_i
=> 0
irb(main):010:0> "fubar".to_i(36)
=> 26608563

-bob