Alan Gauld wrote: > "wesley chun" <[EMAIL PROTECTED]> wrote > >> when you use the 3rd element, it's called the extended slice syntax. > > The ref manual describes use of the third value as simple slicing, > for extended slicing it says this:
<snip> > I've read it three times now and stioll have no idea what its on > about! Extended slicing is used by Numeric and its successors to slice multi-dimensional arrays on multiple dimensions. An extended slice is a simple slice for each dimension of the array, separated by commas. See http://numpy.scipy.org/numpydoc/numpy-6.html#pgfId-36074 AFAIK extended slicing is not supported by any standard Python data types, it was added specifically for Numeric. When an object is indexed with an extended slice, the object's __getitem__() method is passed a tuple of slice objects. It's then up to the object to make sense of it: In [1]: class ext(object): ...: def __getitem__(self, key): ...: print repr(key) ...: ...: In [2]: e=ext() In [3]: e[3] 3 In [4]: e[1:4] slice(1, 4, None) In [5]: e[1:4,2:5] (slice(1, 4, None), slice(2, 5, None)) Kent _______________________________________________ Tutor maillist - [email protected] http://mail.python.org/mailman/listinfo/tutor
