This would simplify the handling of list slices. Slice objects that are produced in a list index area would be different, and optionally the syntax for slices in list indexes would be expanded to work everywhere. Instead of being containers for the start, end, and step numbers, they would be generators, similar to xranges.
Lists would accept these slice objects as indexes, and would also accept any other list or generator. Last, slice objects would be able to be added for multiple index ranges of a list. The new slice object would keep a list of ranges. Optionally, the 1:2 syntax would create a slice object outside of list index areas. It would be shorthand for slice, as [] is for list. This would create some confusion in loops and conditionals due to the colon being used for the end of the structure. (see last example) This would be incompatible with classes that define __setitem__ and __getitem__, and would need changes in how slices are handled in CPython. Therefore, this is probably a proposal for Python 3000. Examples: >>> 1:5 1:5 >>> list(1:5) [1, 2, 3, 4] >>> list(1:5:2) [1, 3] >>> s = 1:3 >>> range(5)[s] [1, 2] >>> 1:5 + 15:17 1:5 + 15:17 >>> range(30)[1:5 + 15:17] [1, 2, 3, 4, 15, 16] >>> range(100)[[1,2,3]] [1, 2, 3] >>> range(100)[1,2,5] # maybe [1, 2, 5] >>> for x in :15:3: print x # maybe 0 3 6 9 12 --- Forrest Voight _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
