Help understanding the decisions *behind* python?
emmanuel.surleau at gmail.com
Fri Jul 31 20:48:03 CEST 2009
On Friday 31 July 2009 19:49:04 Raymond Hettinger wrote:
> On Jul 20, 9:27 am, Phillip B Oldham <phillip.old... at gmail.com> wrote:
> > Specifically the "differences" between lists and tuples have us
> > confused and have caused many "discussions" in the office. We
> > understand that lists are mutable and tuples are not, but we're a
> > little lost as to why the two were kept separate from the start. They
> > both perform a very similar job as far as we can tell.
> The underlying C code for the two is substantially the same. In terms
> of code, tuples are in effect just immutable lists that have the
> feature of being hashable (and therefore usable as dictionary keys or
> elements of sets).
> Beyond the mutable/hashable distinction, there is an important
> philosophical distinction articulated by Guido. He deems tuples
> to be useful for struct like groupings of non-homogenous fields
> and lists to be useful for sequences of homogenous data suitable
> for looping.
> While nothing in the list/tuple code requires you to make that
> it is important because that philosophy pervades the language. If you
> follow Guido's direction, you'll find that the various parts of the
> language fit together better. Do otherwise and you'll be going
> the grain.
I might be wrong, but I get the impression that many people don't indeed "get
it" and use tuples as static arrays and lists when the array needs to be
dynamically resized. This is certainly how I use them as well.
This would tend to show that Guido's notion here was not particularly
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