hex(-5) => Futurewarning: ugh, can't we have a better hex than '-'[:n<0]+hex(abs(n)) ??

[Juha Autero]

Freddie <oinkfreddie at oinkshlick.oinknet> writes:

>> There is a thread from this morning ("bitwise not ...") - this should be an
>> excellent contribution!
>> I have no mercy with someone writing hex(-5)
>> 
>> Kindly
>> Michael P
>> 
>> 
>
> What about crazy people like myself? If you generate a crc32 value with zib, 
> you occasionally get a negative number returned. If you try to convert that 
> to hex (to test against a stored CRC32 value), it spits out a FutureWarning 
> at me. 

Read the thread about bitwise not. Tell Python how many bits you
want. In case of CRC32 that is of course 32 bits:
hex(-5&2**32-1)

Two questions: What is the best way to generate bitmask of n bits all
ones? And would sombody explain why hexadecimal (and octal) literals
behave differently from decimal literals? (see:
http://www.python.org/doc/current/ref/integers.html ) Why hexadecimal 
literals from 0x80000000 to 0xffffffff are interpetred as negative
numbers instead of converting to long integers? 

-- 
Juha Autero
http://www.iki.fi/jautero/
Eschew obscurity!