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Re: precedence for ReplaceAll?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg110622] Re: precedence for ReplaceAll?
  • From: Bill Rowe <readnews at sbcglobal.net>
  • Date: Tue, 29 Jun 2010 06:58:22 -0400 (EDT)

On 6/28/10 at 2:28 AM, siegman at stanford.edu (AES) wrote:

>In article <i073p5$kn0$1 at smc.vnet.net>,
>Bill Rowe <readnews at sbcglobal.net> wrote:

>>Sure, it might be reasonable to think the way the OP indicated. But
>>to do so will clearly get in the way of using Mathematica
>>efficiently. It is understanding what Mathematica actually does
>>that is important here.

>Quite true.

>But if what Mathematica actually does differs, in some unexpected or
>arcane (or hidden) way, from what reasonable, or reasonably
>experienced, users might expect it to do -- and there certainly are
>some examples of this in Mathematica -- that's of some importance
>also.

If someone reasonably experienced in using Mathematica
encounters behavior they do not expect, then they gain more
experience with Mathematica and hopefully learn more about
Mathematica. What else could happen?

>Situations where this happens generally don't mean that Mathematica
>has to change its behavior -- that's not a realistic expectation in
>most cases.  But they do indicate that Wolfram might want to improve
>its documentation in those particular cases.

I am not sure what outcome you are looking for here. Someone
such as myself with lots of experience with Mathematica wouldn't
look at the documentation prior to encountering your
hypothesized arcane characteristic. And given the size of the
documentation, the motivation for reading documentation is
either an unexpected result or trying to use some aspect of
Mathematica one is not experienced with. So, better
documentation will not prevent one from getting unexpected results.

My approach when I do encounter unexpected results is to first
verify I have done what I intended to do. This is usually the
source of my problems. If I have verified things are as I
intended and still get unexpected results, I use tools such as
Trace and FullForm in combination with the documentation for the
functions I am using to understand what is going on. So far,
this approach has always led to my understanding of why things
work the way they do. And it seems to me this is all I can
expect of the documentation.



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