[Tutor] methods versus functions (using lists as an example)

[Bill Mill]

Hans,

max() and min() are not class methods because they are useful outside
the context of lists. For example:

>>> max(1,2,3,4,5,4)
5

Thus, making max and min methods of the list class (or of all sequence
classes) doesn't really make sense.
Now, sum() is a bit more complicated at first blush, but not really.
We want sum to work with all numerical sequence types - namely, lists
*and* tuples. Since tuples have no public methods, and we don't want
to repeat ourselves by including sum() as a method for both lists and
tuples, we make it a global function.

Peace
Bill Mill
bill.mill at gmail.com

PS I don't know the exact reason behind sum(), so I took a shot at it.
That's just how I made sense of it; if you know better please
contradict me.


On Tue, 19 Oct 2004 15:29:45 +0100 (BST), Hans Fangohr
<h.fangohr at soton.ac.uk> wrote:
> Dear all,
> 
> I was looking at what you can do with lists in Python. There are
> basically two sets of commands: (i) methods doing something with a
> list (such as sort(), reverse(), count(), ...) and (ii) functions that
> take a list as an argument (such as sum(), max(), min()).
> 
> I would expect that there is a rationale behind this choice -- would
> anyone know what this is or where I can find more information?
> 
> Many thanks,
> 
> Hans
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