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Re: Verifying a list is alphabetized

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Roedy Green wrote:
> On Fri, 02 Dec 2011 05:58:17 -0800, Patricia Shanahan <pats@acm.org>
> wrote, quoted or indirectly quoted someone who said :
> 
>> Generally, if you are scanning a List that is not known to implement
>> RandomAccess, it is better use Iterator-based methods as much as
>> possible. They are almost as fast as indexed access for RandomAccess
>> lists, and much faster for the other List implementations.
> 
> I forgot all about that. I had ArrayList in mind as the only
> possibility. Will fix.
> 
> ISTR there is a way of knowing if a List can be indexed efficiently.  

Check for instanceof java.util.RandomAccess: "Marker interface used by
List implementations to indicate that they support fast (generally
constant time) random access. The primary purpose of this interface is
to allow generic algorithms to alter their behavior to provide good
performance when applied to either random or sequential access list."

For the inOrder check, I am not sure there would be enough performance
difference to make it worth checking - the general version should be
almost as fast as the indexed version for indexed lists. The sort of
situation in which I might use would be sort. The copy to an array is
unnecessary for RandomAccess.

> 
> Posting code is so often humiliating, but you learn quite a bit in the
> process, and end up with higher quality code all over.  We need to
> teach people to lose their fear of posting code.  You notice how
> terrified newbies are of posting code.  I wonder why...

I know the feeling. We've both been programming long enough to know how
often another programmer will pick up an issue - that is the point of
practices like pair programming and frequent code reviews.

I think newbies take it a bit personally, but sometimes criticism in
this group gets directed too much to the programmer rather than the program.

Patricia

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Thread

Verifying a list is alphabetized laredotornado <laredotornado@zipmail.com> - 2011-11-30 07:52 -0800
  Re: Verifying a list is alphabetized Knute Johnson <nospam@knutejohnson.com> - 2011-11-30 08:05 -0800
    Re: Verifying a list is alphabetized Lew <lewbloch@gmail.com> - 2011-11-30 11:18 -0800
    Re: Verifying a list is alphabetized Arne Vajhøj <arne@vajhoej.dk> - 2011-12-02 19:54 -0500
      Re: Verifying a list is alphabetized Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-03 07:44 -0500
        Re: Verifying a list is alphabetized Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-03 09:02 -0500
        Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 20:05 -0800
          Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 22:13 -0800
            Re: Verifying a list is alphabetized Tom Anderson <twic@urchin.earth.li> - 2011-12-04 21:47 +0000
          Re: Verifying a list is alphabetized Martin Gregorie <martin@address-in-sig.invalid> - 2011-12-04 12:42 +0000
            Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-12-04 12:18 -0800
              Re: Verifying a list is alphabetized Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-12-04 13:17 -0800
                Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-12-04 15:32 -0800
                Re: Verifying a list is alphabetized markspace <-@.> - 2011-12-04 15:59 -0800
                Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-12-04 16:14 -0800
                Re: Verifying a list is alphabetized markspace <-@.> - 2011-12-04 17:12 -0800
                Re: Verifying a list is alphabetized Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-04 21:17 -0500
            Re: Verifying a list is alphabetized Tom Anderson <twic@urchin.earth.li> - 2011-12-04 22:11 +0000
              Re: Verifying a list is alphabetized Martin Gregorie <martin@address-in-sig.invalid> - 2011-12-04 23:41 +0000
              Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-12 01:39 -0800
          Re: Verifying a list is alphabetized Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-04 08:47 -0500
          Re: Verifying a list is alphabetized Gene Wirchenko <genew@ocis.net> - 2011-12-04 21:34 -0800
  Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-11-30 12:52 -0800
    Re: Verifying a list is alphabetized laredotornado <laredotornado@zipmail.com> - 2011-12-01 06:43 -0800
  Re: Verifying a list is alphabetized Joshua Maurice <joshuamaurice@gmail.com> - 2011-11-30 13:16 -0800
  Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-02 01:43 -0800
    Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-12-02 05:58 -0800
      Re: Verifying a list is alphabetized Arne Vajhøj <arne@vajhoej.dk> - 2011-12-02 19:55 -0500
      Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 02:54 -0800
        Re: Verifying a list is alphabetized Patricia Shanahan <pats@acm.org> - 2011-12-03 06:17 -0800
    Re: Verifying a list is alphabetized Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 03:10 -0800
  Re: Verifying a list is alphabetized Arne Vajhøj <arne@vajhoej.dk> - 2011-12-02 19:52 -0500

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