Slice inconsistency?

Terry Reedy tjreedy at udel.edu
Sat Sep 27 19:15:34 CEST 2003


"Roberto A. F. De Almeida" <roberto at dealmeida.net> wrote in message
news:10c662fe.0309270545.1fd5d839 at posting.google.com...
> Stephen Horne <$$$$$$$$$$$$$$$$$@$$$$$$$$$$$$$$$$$$$$.co.uk> wrote
in message news:<bqeanvgel9ra3va44j090bmn2l126t340g at 4ax.com>...
> > That is, whether the single or multiple notation is used, and
whether
> > the slice objects are placed in a tuple or not, they are
constructed
> > from the tuple notation - the translation from notation to slice
> > object should be done consistently.
>
> Yes, I believe I was not very clear. This is the inconsistency I was
> talking about. (And this is with Python 2.3.1)

As I pointed out in response to the same message, there is no
inconsistency because the premise behind that conclusion is wrong.  I
also pointed out that you can make the premise true and get the
consistency you expect by adding a comma after single slice
expressions so that you do always use tuple notation.

[me]> > >What you probably want is b[:-1][:-1], etc.  Each index must
be
> > >separately bracketed to access items in list of lists (etc).

> The problem with b[:-1][:-1] is that it will return b[:-1], and then
> slice the result again. It's ok if you're working with lists, but
not
> for what I'm doing.
...
> and request from the server only the data that will be used, and
> return it as a Numeric array.

Then you should, of course, use N.P.'s extended slicing syntax and I
would expect all to work well.  If you are doing something just
similar, then you will have to do similar custom interpretation of
slice tuples.

Terry J. Reedy






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