On Sun, 27 Jul 2008 16:57:14 +0200, "Diez B. Roggisch" <[EMAIL PROTECTED]>
wrote:
>Marc 'BlackJack' Rintsch schrieb:
>> On Sun, 27 Jul 2008 16:41:19 +0200, Diez B. Roggisch wrote:
>>
>>> DaveM schrieb:
>>>> Getting back to the list concatenation, I finally found the
>>>> itertools.chain
>>>> command which is the most compact and fastest (or second fastest by a
>>>> trivial amount, I can't remember which). Along the way, I must have
>>>> tried/used half a dozen methods, ...which brings me back my initial PERL
>>>> comment. There's more than one way to do it in Python, too.
>>> But I *do* know that taking the python zen literally is fruitless.
>> I think it should be taken more literally than the wrong reduction to
>> "there should be only one way". People tend to forget "obvious" and
>> "preferably" all the time.
>Good point. The OP found the obvious way of extending. I wonder what his
>reasons were to abandon it.
You'll have guessed, I'm sure, that I'm not a professional programmer. This
was the third rewrite of a program to match candidate groups to examiners on
a three day course I run, necessitated on this occasion by a change in the
structure of the course. I originally learnt python as I wrote, and some of
the early code was ugly and verbose, so once the current rewrite was working
I took the opportunity to tidy the code up and document it (yes, I know, but
as I said, I'm an amateur). The list concatenation was an itch I couldn't
scratch:
temp = []
for value in sessexam.values():
temp.extend(value)
c_exam = [name for name in set(temp)] #See what I mean about verbose?
c_exam.sort()
return c_exam
Six lines just didn't feel like it ought to be the best way to do something
so simple. I liked the attempt below better, but was foolish enough to time
it, so that was the end of that.
return sorted(list(set(reduce(lambda x, y: x+y, sessexam.values()))))
The current version (below) is a compromise, but I still feel there _ought_
to be a simple one word command to join multiple lists.
a = list(set(itertools.chain(*sessexam.values())))
a.sort() #As I write I'm wondering if I really need it sorted. Hmm...
return a
DaveM
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