hashing strings to integers for sqlite3 keys

[Adam Funk]

On 2014-05-22, Chris Angelico wrote:

> On Thu, May 22, 2014 at 11:54 PM, Adam Funk <a24061 at ducksburg.com> wrote:

>> That ties in with a related question I've been wondering about lately
>> (using MD5s & SHAs for other things) --- getting a hash value (which
>> is internally numeric, rather than string, right?) out as a hex string
>> & then converting that to an int looks inefficient to me --- is there
>> any better way to get an int?  (I haven't seen any other way in the
>> API.)
>
> I don't know that there is, at least not with hashlib. You might be
> able to use digest() followed by the struct module, but it's no less
> convoluted. It's the same in several other languages' hashing
> functions; the result is a string, not an integer.

Well, J*v* returns a byte array, so I used to do this:

    digester = MessageDigest.getInstance("MD5");
    ...
    digester.reset();
    byte[] digest = digester.digest(bytes);
    return new BigInteger(+1, digest);

I dunno why language designers don't make it easy to get a single big
number directly out of these things.


I just had a look at the struct module's fearsome documentation &
think it would present a good shoot(self, foot) opportunity.


-- 
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?