Sorry Gary,
I found out that I wasn't reassigning the array back once I got the first 4
bytes. I don't mean to appear lazy..:(
Thanks for the help!
-M
> Date: Thu, 15 May 2008 09:51:22 -0700> From: [EMAIL PROTECTED]> To: [EMAIL
> PROTECTED]> CC: python-list@python.org> Subject: Re: How do I use the unpack
> function?> > Marlin Rowley wrote:> > Thanks for the advice!> > > > However, I
> assumed that:> > > > fourbytes = pixelComponent[:4]> > > > would shave that
> byte off the array in pixelComponent. So that the > > array is smaller by one
> on the next iteration. Is this not the case?> You don't need the newsgroup to
> answer this kind of question. Just try it!> > >>> a = 'abcdefghi'> >>> b =
> a[:4]> >>> print a,b> abcdefghi abcd> > Notice that the [:4] index does not
> change the original array.> > Gary Herron> > > > > > > I'm getting weird
> results now..> > > > -M> >> >> >> >> >
> ------------------------------------------------------------------------> >>
> > > Date: Thu, 15 May 2008 09:11:23 -0700> > > From: [EMAIL PROTECTED]> > >
> To: [EMAIL PROTECTED]> > > CC: python-list@python.org> > > Subject: Re: How
> do I use the unpack function?> > >> > > Marlin Rowley wrote:> > > > All:> > >
> >> > > > I've got a script that runs really slow because I'm reading from a>
> > > > stream a byte at a time:> > > >> > > > // TERRIBLE> > > > for y in
> range( height ):> > > > for color in range(4):> > > > for x in range( width
> ):> > > > pixelComponent = fileIO.read(4)> > > > buffer =
> unpack("!f",pixelComponent) << unpacks ONE> > > > float, but we now can do
> something with that pixel component.> > > >> > > >> > > > I can speed this up
> dramatically if I did this:> > > >> > > > // MUCH FASTER> > > > for y in
> range( height ):> > > > for color in range(4):> > > > pixelComponent =
> fileIO.read(4*width) <<<<<<<<< GET a LOT more> > > > data from the stream
> into memory FIRST!!> > > > for x in range( width ):> > > > buffer = unpack(
> ?????? ) <<<< how do I get each float from> > > > the pixelComponent???> > >>
> > > Just carve of the first four bytes of pixelComponent on each pass> > >
> through the loop, and unpack that.> > >> > > for x in range(width):> > >
> fourbytes = pixelComponent[:4] # first 4 bytes> > > pixelComponent =
> pixelComponent[4:] # All but first four bytes> > > buffer = unpack("!f",
> fourbytes)> > >> > >> > > There are probably better ways overall, but this
> directly answers your> > > question.> > >> > > Gary Herron> > >> > >> > > >>
> > > >> > > > -M> > > > > >
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