[Edu-sig] Re: In defense of 0, was Re: None potato, one potato, two potato, more..

[Trent Oliphant]

> 
>>So the indexing notation [n] could be considered shorthand for [n:n+1]? 
>> You are taking a slice of len 1 starting at n?
> 
> 
> But where [n:n+1] is a sequence of length 1, [n] is the object in that
> sequence.
> 
> 	>>> x = ['a', 'b', 'c', 'd']
> 	>>> x[2:3]
> 	['c']
> 	>>> x[2]
> 	'c'
> 
> If Python had a 'first' method for sequences, similar to 'car' in
> Lisp, then x[n] would be roughly equivalent to x[n:n+1].first().
> 

Of course you are correct that they are not truly equivalent.  That is 
the problem with any model - at some point it breaks down.  I know that 
I have a tendency to create models that work for me to understand - and 
then I know the limitation of the model.  Isn't that one of the 
challenges of teaching - finding a common ground for understanding?

Trent