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Groups > comp.lang.python > #82458

Re: Extension of while syntax

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On Thu, 11 Dec 2014 18:21:46 -0800 (PST), Nelson Crosby <nc@sourcecomb.com>
declaimed the following:

>I was thinking a bit about the following pattern:
>
>value = get_some_value()
>while value in undesired_values:
>    value = get_some_value()
>
>I've always hated code that looks like this. Partly due to the repetition, but partly also due to the fact that without being able to immediately recognise this pattern, it isn't very readable.
>

	So what's wrong with

while True:
	value = get_some_value()
	if value not in undesired_values: break

Closest match to Ada

loop
	value := get_some_value;
	exit when value not in undesired_values;
end loop;

(the "not in" may need to be a function receiving value and returning a
boolean, if value can be some arbitrary item -- Ada normally only allows
"in" for a range, not a list/array; though 2012 allows v1|v2|v...|vx )
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

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Thread

Extension of while syntax Nelson Crosby <nc@sourcecomb.com> - 2014-12-11 18:21 -0800
  Re: Extension of while syntax Ben Finney <ben+python@benfinney.id.au> - 2014-12-12 13:37 +1100
  Re: Extension of while syntax Chris Angelico <rosuav@gmail.com> - 2014-12-12 13:38 +1100
    Re: Extension of while syntax Marko Rauhamaa <marko@pacujo.net> - 2014-12-12 09:10 +0200
      Re: Extension of while syntax Chris Angelico <rosuav@gmail.com> - 2014-12-12 18:38 +1100
        Re: Extension of while syntax Marko Rauhamaa <marko@pacujo.net> - 2014-12-12 10:25 +0200
      Re: Extension of while syntax cl@isbd.net - 2014-12-12 09:09 +0000
        Re: Extension of while syntax Marko Rauhamaa <marko@pacujo.net> - 2014-12-12 12:33 +0200
  RE: Extension of while syntax "Clayton Kirkwood" <crk@godblessthe.us> - 2014-12-11 18:59 -0800
  Re: Extension of while syntax Terry Reedy <tjreedy@udel.edu> - 2014-12-11 22:00 -0500
  Re: Extension of while syntax Ben Finney <ben+python@benfinney.id.au> - 2014-12-12 14:14 +1100
  Re: Extension of while syntax Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-12 08:00 +0000
  Re: Extension of while syntax Chris Angelico <rosuav@gmail.com> - 2014-12-12 19:05 +1100
  Re: Extension of while syntax Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-12-12 11:38 -0500
  Re: Extension of while syntax Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-13 22:56 +1100

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