On Sunday, October 28, 2012 10:14:03 PM UTC-7, Paul Rubin wrote: > Andrew writes: > > > So: Why does python choose to convert them to positive indexes, and > > > have slice operate differently than xrange > > > > There was a thread a few years back, I think started by Bryan Olson, > > that made the case that slice indexing is a Python wart for further > > reasons than the above, and suggesting a notation like x[$-5] to denote > > what we now call x[-5] (i.e. $ is the length of the string). So your > > example x[$-4:3] would clearly be the same thing as x[6:3] and not give > > any suggestion that it might wrap around.
I'm getting very frustrated with the editor provided for this group... It keeps posting prematurely, and putting my email in even when I tell it not to each time; and there is no way to edit a post... but deleting is ok... I think Olson makes a good point. The len() operator is so ubiquitous that it would be very useful to have a shorthand like that. I'll have to look for his thread. I'm thinking that I might just patch my version of Python 3.x, in C, to allow iterators to be passed to __getitem__; I haven't ever seen someone wanting to use mixed sign indexes to extract a small chunk of an array in the middle; so I don't think my patch will break existing code. The snippets of code given by other posters in the thread might also be used to make a compatibility wrapper; I'll have to study it closer; so that distributed code would still work on unpatched python, albeit much slower. -- http://mail.python.org/mailman/listinfo/python-list
