Slice lists and extended slicing

[Terry Reedy]

On 1/26/2011 12:52 PM, Benjamin Kaplan wrote:

> If you're trying to learn a language, I would suggest reading
> tutorials, not the grammar.

I second that.

> As you can see from the error thrown, the
> operation is syntactically valid (you don't get a syntax error). It's
> just that lists don't accept them. I don't know of any built-in data
> type that takes slice lists but numpy matrices will.
>
>>>> a = numpy.matrix([[1,2,3],[4,5,6],[7,8,9]])
> matrix([[1, 2, 3],
>          [4, 5, 6],
>          [7, 8, 9]])
>
>>>> a[0:2,1:3]
> matrix([[2, 3],
>          [5, 6]])

Which is to say, slice lists are a specialized feature added 
specifically for numerical python, now numpy. Ignore then unless and 
until you happen to install and use numpy, or something similar that 
also uses them.

-- 
Terry Jan Reedy