Tutorial creates confusion about slices

[Steve Holden]

Antoon Pardon wrote:
> On 2007-04-25, Ant <antroy at gmail.com> wrote:
>> On Apr 23, 1:38 pm, Antoon Pardon <apar... at forel.vub.ac.be> wrote:
>>> The following is part of the explanation on slices in the
>>> tutorial:
>>>
>>> The best way to remember how slices work is to think of the indices as
>> ...
>>>   +---+---+---+---+---+
>>>   | H | e | l | p | A |
>>>   +---+---+---+---+---+
>>>   0   1   2   3   4   5
>>>  -5  -4  -3  -2  -1
>> For a tutorial this is sound advice. A tutorial is designed to give
>> readers an easy intro to a topic, which is what this achieves. At this
>> stage the target audience has no idea that extended slices even exist,
>> let alone that you can use negative indices with them.
> 
> OK. But eventually they will come into contact with negative indexes.
> If they still rely on the above representation for understanding slices
> that may cause confusions. It is possible that the time lost in clearing
> up these later confusions will be bigger than the time gained by using
> this simplification in the tutorial.
> 
> So I'm not so sure it is sound advice in this case.
> 
> If the consensus is that something like this should remain, I would
> suggest replacing:
> 
>     "The best way to remember how slices work is"
> 
> with:
> 
>     "A way to remember how slices work, it is not entirly correct
>      but may be usefull, is"
> 
> Or something similar.
> 
> 
> Wording to that effect makes it more clear that it is a crutch
> that can be usefull now but that it should be discarded later.
> 
Most people reading a tutorial are aware that they are being given the 
knowledge they need to put the subject matter to immediate use, and that 
there may well be refinements that are glossed over or covered in detail 
later or elsewhere.

I don't believe this needs to be made explicit wherever it applies.

regards
  Steve
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