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Re: Best way to check that you are at the beginning (the end) of an iterable?

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On 08Sep2011 14:21, Chris Torek <nospam@torek.net> wrote:
| In article <mailman.854.1315441399.27778.python-list@python.org>
| Cameron Simpson  <cs@zip.com.au> wrote:
| >Facilities like feof() in C and eof in Pascal already lead to lots of
| >code that runs happily with flat files and behaves badly in interactive
| >or piped input. It is _so_ easy to adopt a style like:
| >
| >  while not eof(filehandle):
| >    line = filehandle.nextline()
| >    ...
| 
| Minor but important point here: eof() in Pascal is predictive (uses
| a "crystal ball" to peer into the future to see whether EOF is is
| about to occur -- which really means, reads ahead, causing that
| interactivity problem you mentioned), but feof() in C is "post-dictive".
| The feof(stream) function returns a false value if the stream has
| not yet encountered an EOF, but your very next attempt to read from
| it may (or may not) immediately encounter that EOF.

Thanks. I had forgotten this nuance. Cheers,
-- 
Cameron Simpson <cs@zip.com.au> DoD#743
http://www.cskk.ezoshosting.com/cs/

                          "Where am I?"
                        "In the Village."
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                         "Information."
                    "Whose side are you on?"
"That would be telling. We want information. Information. Information!"
                       "You won't get it!"
                 "By hook or by crook, we will."
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                       "The new number 2."
                       "Who is number 1?"
                       "You are number 6."
              "I am not a number, I am a free man!"
                           [Laughter]

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Best way to check that you are at the beginning (the end) of an iterable? Laurent <laurent.payot@gmail.com> - 2011-09-07 14:35 -0700
  Re: Best way to check that you are at the beginning (the end) of an iterable? Cameron Simpson <cs@zip.com.au> - 2011-09-08 08:48 +1000
    Re: Best way to check that you are at the beginning (the end) of an iterable? Laurent <laurent.payot@gmail.com> - 2011-09-07 16:22 -0700
    Re: Best way to check that you are at the beginning (the end) of an iterable? Laurent <laurent.payot@gmail.com> - 2011-09-07 16:22 -0700
      Re: Best way to check that you are at the beginning (the end) of an iterable? Cameron Simpson <cs@zip.com.au> - 2011-09-08 10:23 +1000
        Re: Best way to check that you are at the beginning (the end) of an iterable? Laurent <laurent.payot@gmail.com> - 2011-09-07 17:53 -0700
        Re: Best way to check that you are at the beginning (the end) of an iterable? Laurent <laurent.payot@gmail.com> - 2011-09-07 17:53 -0700
        Re: Best way to check that you are at the beginning (the end) of an iterable? Chris Torek <nospam@torek.net> - 2011-09-08 14:21 +0000
          Re: Best way to check that you are at the beginning (the end) of an iterable? Cameron Simpson <cs@zip.com.au> - 2011-09-09 08:39 +1000
      Re: Best way to check that you are at the beginning (the end) of an iterable? Tim Chase <python.list@tim.thechases.com> - 2011-09-07 19:01 -0500
        Re: Best way to check that you are at the beginning (the end) of an iterable? Laurent <laurent.payot@gmail.com> - 2011-09-07 18:08 -0700
        Re: Best way to check that you are at the beginning (the end) of an iterable? Laurent <laurent.payot@gmail.com> - 2011-09-07 18:08 -0700
      Re: Best way to check that you are at the beginning (the end) of an iterable? Terry Reedy <tjreedy@udel.edu> - 2011-09-07 21:06 -0400
    Re: Best way to check that you are at the beginning (the end) of an iterable? Peter Otten <__peter__@web.de> - 2011-09-09 13:04 +0200
      Re: Best way to check that you are at the beginning (the end) of an iterable? Chris Angelico <rosuav@gmail.com> - 2011-09-09 21:30 +1000
  Re: Best way to check that you are at the beginning (the end) of an iterable? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-09-08 10:24 +1000
    Re: Best way to check that you are at the beginning (the end) of an iterable? Terry Reedy <tjreedy@udel.edu> - 2011-09-07 21:08 -0400
    Re: Best way to check that you are at the beginning (the end) of an iterable? Laurent <laurent.payot@gmail.com> - 2011-09-07 18:05 -0700
  Re: Best way to check that you are at the beginning (the end) of an iterable? Miki Tebeka <miki.tebeka@gmail.com> - 2011-09-07 17:24 -0700
    Re: Best way to check that you are at the beginning (the end) of an iterable? Laurent <laurent.payot@gmail.com> - 2011-09-07 18:06 -0700
    Re: Best way to check that you are at the beginning (the end) of an iterable? Chris Rebert <clp2@rebertia.com> - 2011-09-07 19:27 -0700

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