On Wed, Nov 14, 2018 at 5:14 AM David Allemang wrote:
>
> That is not what slice.indices does. Per help(slice.indices) -
>
> "S.indices(len) -> (start, stop, stride)
>
> "Assuming a sequence of length len, calculate the start and stop indices, and
> the stride length of the extended slice
That is not what slice.indices does. Per help(slice.indices) -
"S.indices(len) -> (start, stop, stride)
"Assuming a sequence of length len, calculate the start and stop indices,
and the stride length of the extended slice described by S. Out of bounds
indices are clipped in a manner consistent
On Mon, Nov 12, 2018 at 4:43 PM Nicholas Harrison
wrote:
> Only when this is called (implicitly or explicitly) do checks for valid
> objects and bounds occur. From my experience using slices, this is how they
> work in that context too.
On reconsideration, I've found one more argument in
On Mon, Nov 12, 2018 at 11:23:21AM -0500, David Mertz wrote:
> >>> import pandas as pd
> >>> import numpy as np
> >>> I = pd.IndexSlice
> >>> J = np.s_
> >>> I[4:10:3]
> slice(4, 10, 3)
I'm not entirely sure that I like the idea of conflating slice
*constructor* with slice *usage*. Slice
For sake of completeness, here is another possible problem I've found with
it.
I was afraid of making something context-dependent, and therefore breaking
its consistency. Here is the use of slices in the current language that
breaks my rules:
my_array[:,2] # valid syntax, though I've typically
I mostly like the abstraction being proposed, but the syntactical edge
cases like `[::3]` (infinite list crashes) and {4:10} (a dict not a
slice/range set) tip the balance against it for me. Saying to add some
various stars and parens in various not-really-obvious places just makes
the proposal
That's true. I should clarify what I was thinking a bit more. Maybe it's
better to say that the new syntax creates a slice object:
(::) # this creates slice(None, None, None)
It accepts any object into its arguments and they default to None when they
are left off. This can be passed into list
Interesting. I haven't looked at that package before. It looks like it
would work well for that.
On Sun, Nov 11, 2018 at 4:48 AM Robert Vanden Eynde
wrote:
> I'm wondering how your examples would go with from funcoperators import
> infix (https://pypi.org/project/funcoperators/)
>
> sum(1:6) #
Overall, I agree with you. It is more intuitive to an experienced Python
user, and not so helpful to beginners. It decreases the ability to read out
code like English sentences and makes it harder to know what to search for
online. So it boosts facility after you know the language, but not when
That's a good point.
It might be better to disallow the list and set versions all together. To
get a list or set you would instead have to explicitly unpack a range/slice
object:
[*(:5)] # [:5] no longer allowed
{*(1:6)} # {1:6} is a dict
That would also solve the misstep of the
On Sun, Nov 11, 2018 at 04:34:16PM +, Juancarlo Añez wrote:
> On Sun, Nov 11, 2018 at 6:00 AM Chris Angelico wrote:
>
> > Be careful of this last one. If you omit the step, it looks like this:
> >
> > {start:stop}
> >
> > which is a dictionary display.
> >
>
> The parenthesis could always
On Sun, Nov 11, 2018 at 6:00 AM Chris Angelico wrote:
> Be careful of this last one. If you omit the step, it looks like this:
>
> {start:stop}
>
> which is a dictionary display.
>
The parenthesis could always be required for this new syntax.
In [*1*]: {'a':1}
Out[*1*]: {'a': 1}
In [*2*]:
On Sun, Nov 11, 2018 at 6:59 AM Nicholas Harrison
wrote:
> Any of the values may be omitted and in the slice context the behavior has no
> changes from what it already does: start and stop default to the beginning or
> end of the list depending on direction and the step defaults to 1.
Just to
I'm wondering how your examples would go with from funcoperators import
infix (https://pypi.org/project/funcoperators/)
sum(1:6) # instead of sum(range(1, 6))
>
>
sum(1 /exclusive/ 6)
list(1:6)
>
>
list(1 /exclusive/ 6)
set(1 /exclusive/ 1)
Note that you can pick another name.
Note that you can
On Sat, Nov 10, 2018 at 10:58:02PM -0700, Nicholas Harrison wrote:
[...]
> (start:stop:step)
>
>
> Meet a range/slice object. Parentheses are required. (Its syntax in this
> regard follows exactly the same rules as a generator expression.) I say
> both range and slice because it can be used in
On Sun, Nov 11, 2018 at 4:59 PM Nicholas Harrison
wrote:
> It has a couple of siblings that should be obvious (think list or set
> comprehension):
>
> [start:stop:step] # gives a list
> {start:stop:step} # gives a set
>
Be careful of this last one. If you omit the step, it looks like this:
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