How do you do arrays

[Alex Martelli]

Kartic <kartic.krishnamurthy at gmail.com> wrote:
   ...
> I am not sure what book you are using but I don't think it is a very
> good one.

Hmmm, considering he said it's "Python in a Nutshell", I disagree with
you;-).  If he had understood that he probably wanted to use lists, not
arrays, the top paragraph on p. 47 might have helped him -- "Assigning
to an item with an invalid index also raises an exception", and list
comprehensions are on p. 56.

But considering that in the first post he was just trying to assign to
an indexing on a name he had never bound at all, it seems to me that
starting with the Nutshell may simply have been a bit of "running before
you can walk".  The Nutshell does mention that names (variables) spring
into existence when you bind them, which implies they don't exist
previously, and thus you can't perform any operation on them (such as
binding an indexing on them) before you're bound them; but the Nutshell
doesn't extensively belabor the point.

I tried to explain this issue to another poster who recently appeared to
want to turn the Nutshell into a lay version of the Heart Sutra
("Therefore, Shariputra, in Python there are no declarations.  There is
no use strict, no option explicit, no implicit none; no type of a name
and no declaring of a name so that it can't be rebound, no defining of a
name's type and no omitting to define a name's type, ...").  In a quick
reference, there just isn't enough space to repeat every key point, much
less to belabor the implications of each; even if space were free,
having to skip through such repetitions would _waste_ time for the main
target audience -- people who know some Python and want to get reminded
of every detail about a certain subject, or just look up something
specific.  Trying to make a book that's both a hand-holding tutorial
_and_ a quick reference would produce a book that is not very good at
either task, IMHO.


Alex