On Fri, 10 Oct 2008 00:30:18 +0200, Hendrik van Rooyen wrote:
You'll find that in most cases, using integer or Boolean is enough. There
are some edge cases, which requires bit addressing for speed or memory
optimizations, in python, the usual response to that kind of optimization
requirement is to move that part of the code to C.
If, for the more usual case, you require the bit addressing because the
data structure is more convenient to work with that way, you could use a
class that implements the __getitem__, __setitem__, and a "join" method.
anyway, if you used str, it isn't hard to have both behavior (easy
indexing and easy joining) the bits:
('0', '1')
'01101010'
106
'j'
....
....
Is there a canonical way to address the bits in a structure like an
array or string or struct?
>
Or alternatively, is there a good way to combine eight ints that
represent bits into one of the bytes in some array or string or
whatever?
>
It seems to me that there is a dilemma here :
>
if you can write:
>
bit3 = 1
>
Then you have to jump through hoops to get bit0 through bit7 into some
byte that you can send to an i/o routine.
>
On the other hand, if you keep the bits "in" the byte, then you can
write:
>
byte[3] = '\x7e'
>
but you have to jump through hoops to get at the individual bits.
>
Is there a "best" way?
>
It would be nice to be able to write:
>
if io.byte2.bit3:
do_something()
>
if io.byte2 == alarm_value:
do_something_el se()
>
where:
>
io.byte2 & 8 "is" io.byte2.bit3
>
Is this possible?
>
- Hendrik
array or string or struct?
>
Or alternatively, is there a good way to combine eight ints that
represent bits into one of the bytes in some array or string or
whatever?
>
It seems to me that there is a dilemma here :
>
if you can write:
>
bit3 = 1
>
Then you have to jump through hoops to get bit0 through bit7 into some
byte that you can send to an i/o routine.
>
On the other hand, if you keep the bits "in" the byte, then you can
write:
>
byte[3] = '\x7e'
>
but you have to jump through hoops to get at the individual bits.
>
Is there a "best" way?
>
It would be nice to be able to write:
>
if io.byte2.bit3:
do_something()
>
if io.byte2 == alarm_value:
do_something_el se()
>
where:
>
io.byte2 & 8 "is" io.byte2.bit3
>
Is this possible?
>
- Hendrik
are some edge cases, which requires bit addressing for speed or memory
optimizations, in python, the usual response to that kind of optimization
requirement is to move that part of the code to C.
If, for the more usual case, you require the bit addressing because the
data structure is more convenient to work with that way, you could use a
class that implements the __getitem__, __setitem__, and a "join" method.
anyway, if you used str, it isn't hard to have both behavior (easy
indexing and easy joining) the bits:
>>a = '01101010'
>>a[0], a[1]
>>a[0], a[1]
>>a
>>int(a, 2)
>>chr(int(a, 2))
>>def bin2int(b): return int(a, 2)
>>def bin2chr(b): return chr(int(a, 2))
>>>