On 2007-04-25, Ant <[EMAIL PROTECTED]> wrote: > On Apr 23, 1:38 pm, Antoon Pardon <[EMAIL PROTECTED]> wrote: >> The following is part of the explanation on slices in the >> tutorial: >> >> The best way to remember how slices work is > ... >> +---+---+---+---+---+ >> | H | e | l | p | A | >> +---+---+---+---+---+ >> 0 1 2 3 4 5 >> -5 -4 -3 -2 -1 >> >> This is all very well with a simple slice like: >> >> "HelpA"[2:4] => "lp" >> >> But it give the wrong idea when using the following extended >> slice: >> >> "HelpA"[4:2:-1] => "Ap" > > I think that the tutorial example is absolutely fine as it is.
I object only to the word "best". I don't like the above model because it divorces the indexes that appear in subscripts from those that appear in slices. I 't find it complicated to think: a[2:4] is the contiguous slice of elements starting at the gap between element 1 and 2, and ending at the gap between element 3 and 4. I've always found thinking of [2:4] as a half-open range much easier. I suppose the above model could avoid this notational problem if you say that a[k] means the one element slice a[k:k+1] (technically true for strings, but false for lists), rather than ever thinking of item indexes as pointing directly at an item. So I vote that the word "best" be removed. -- Neil Cerutti When "yearn" was sung, the performers ounded like they were in a state of yearning. --Music Lit Essay -- http://mail.python.org/mailman/listinfo/python-list
