optimization question
Andrew Koenig
ark at research.att.com
Mon Aug 12 10:05:37 EDT 2002
>> Yes, it looks like it would. On the other hand, I might want
>> to generalize the technique to sequences other than strings...
Terry> def subseqmatch(seq, i, j, sub):
Terry> if len(sub) != j-i: return False
Terry> for item in sub:
Terry> if item != seq[i]: return False
Terry> i += 1
Terry> return True
Yes, I can always do it longhand, as it were.
I'd like to take a step back for a moment. I originally asked a
simple question: If I write an expression of the form s[i:j] == x, can
I count on the implementation optimizing it by avoiding a copy of
s[i:j], so that I can be assured of not having to think about finding
more efficient alternatives? So far, in addition to answers to the
question I asked, I have gotten answers to a number of questions that
I did not ask, such as:
Should I replace s[i:j] == x by something else?
Is the mere presence of code of the form s[i:j] == x
in my program evidence of bad design?
Is it proper to ask about the algorithmic complexity
of a programming-language implementation?
All of these may be interesting questions, but they aren't the one
I asked. You're welcome to discuss them, of course, but please don't
assume that I asked them.
--
Andrew Koenig, ark at research.att.com, http://www.research.att.com/info/ark
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