For Guido and developers Python.

[Ype Kingma]

Quiet wrote:

> For Guido and developers Python.
> Hello.
> There is a problem.
> At creation of slice created the copy of elements of the list.
> For many recursive algorithms it would be convenient to create
> a slice as the alias (link) to the list.
>
> Example:
>
> lst_List =.....
>
> def f (lst_List):
>         ....
>          f (lst_List [i:j])
>
> Thus it is necessary, that the list was one. It is necessary that
> copies were not created.
>
> For this purpose I suggest to enter a new key word "aslink".
>
> Example:
>
> f(lst_List [i:j] aslink)
>
> It is possible to make so:
> 1. When it is necessary to make a copy of object obviously:
> "ascopy":
>
> a = b ascopy

You can use:
a = b.copy()

> 2. It is not necessary to create a copy of object.
> The obvious reference to object: aslink:
>
> a = b aslink

Simply use:

a = b


> f(lst_List [i:j] aslink)

You can solve this by defining another function f2

def f2(lst_List, i, j): ...

and always indexing lst_List in f2 with i added to
the index. You might also assert that any resulting
index is smaller than j.
You could use a separate class to encapsulate the
arguments of f2.

Since python does not optimize for tail recursion
you might also change evt. tail recursion to a loop.

Have fun,
Ype


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