Bits from Numbers.

Bengt Richter bokr at oz.net
Fri Jan 9 03:58:20 CET 2004


On Wed, 07 Jan 2004 16:36:43 -0800, sdd <daniels at dsl-only.net> wrote:

>I am whacking away at some code to view numbers as bit sequences.
>While this is not complete, I'd appreciate some feedback from anyone
>who is interested in looking at it:
>     http://members.dsl-only.net/~daniels/bits.html
>
>As the page describes, bit extract of more than an int's worth of bits
>from a long at one go does not yet work.
>
>
>The basic idea is that the (non-complex) python numbers can be
>viewed as an infinite binary bit stream:
>
>     ...........000101.11000.....  is 5.75
>
>There are functions to get the least and most significant bit
>numbers, examine a particular bit, and extract a consecutive
>chunk of bits.
>
>At the bottom of the page are links to source archives and windows
>installers for 2.2 and 2.3.
>
>For now, consider this a pre-alpha.  I am soliciting comments
>on both the definitions and names of the functions provided.
>
>However, I'd like to point out now that negative integers have
>an infinite number of ones _and_ zeros in their expansion above,
>so popcount as traditionally defined for negative integers is
>unworkable.

No time to look now, but maybe 

    http://mail.python.org/pipermail/python-list/2003-December/199683.html

will give you something useful? BTW, it proposes a literal string format that takes
care of the infinitely repeating sign bit problem (i.e., you don't repeat it, except
for representing -1 as '11b' for symmetry with '01b' for +1) but you always have a one
or zero leading bit that you can repeat as needed to make whatever width.

Regards,
Bengt Richter



More information about the Python-list mailing list