Pythonic way to sum n-th list element?
aleax at aleax.it
Tue Apr 22 14:10:39 CEST 2003
> On Mon, 21 Apr 2003 16:02:27 +0000, Alex Martelli wrote:
>> As a bonus -- sum() now returns 0, while in my original design it
>> a ValueError, just like e.g. max() does. I thought raising an error
>> was best in the name of "errors shouldn't pass silently" and "in the face
>> ambiguity, refuse the temptation to guess". But -- once we decree that
>> "sum is about numbers", there's no real ambiguity, so we can have the
>> little extra handiness of having sum() not be an error;-).
> Sum() is a goodness! And sum() returns 0 is a great goodness.
> Thanks Alex.
You're welcome, but for "sum() returns 0" you should thank Guido
and Tim (it would raise a ValueError if I had implemented it my way;-).
[Which may help explain why I use and love a language architected by
Guido (with lots of input from Tim & many others, of course), rather
than one architected by my own self...;-)]
To be properly thankful that we're not using an Alex-designed
language, we might want to look at a simple example from the
domain-specific language BBL (Bridge-Bidding Language) which I
designed and implemented in the '80s [well before I met Python --
but I was quite familiar with Icon, REXX and other highly
readable very-high-level languages, so that's no excuse;-)].
Here's the BBL expression to determine whether the current hand
is suitable for a weak-notrump opener...:
& ( # conditions for a weak-notrump opener
s ( 1 g 4 3 3 3 # shape 4333 (any), or...
2 g 4 4 3 2 # 4432 (any), or...
3 3- 3- 3- 5 # 5332 w 5 clubs, or...
4 3- 3- 5 3- # 5332 w 5 diamonds;
< ( 11 # moreover, a 12-14 range for
\+ SHDC c( 4 3 2 1 0) # normal Milton-Work point-count
There -- aren't you glad I don't do language design any more?-)
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