optimization pointers?

[Mel Wilson]

In article <3fd9cdf1$0$6970$7a628cd7 at news.club-internet.fr>,
"Anthony McDonald" <tonym1972(at)club-internet(in)fr> wrote:
>Heres my contribution, removing the string append in favour of slices. Buys
>a little speed thanks to xrange.
>
>def lz_comp_mine(text):
>    voc = {}
>    st = 0
>    for cur in xrange(1,len(text)+1):
>        if not voc.get(text[st:cur], False):
>            voc[text[st:cur]] = True
>            st = cur
>    return len(voc)

   Nice touch!  I tried slices and took a huge performance
hit (almost 3x the list version) but I didn't use `for ... in
xrange ...`.  It must have all been in the while-loop test
and index incrementing.

        Regards.        Mel.