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From: Tim Chase <python.list@tim.thechases.com>
Newsgroups: comp.lang.python
Subject: Re: Irregular last line in a text file, was Re: Regular expressions
Date: Wed, 4 Nov 2015 09:33:02 -0600
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On 2015-11-04 14:39, Steven D'Aprano wrote:
> On Wednesday 04 November 2015 03:56, Tim Chase wrote:
>> Or even more valuable to me:
>> 
>>   with open(..., newline="strip") as f:
>>     assert all(not line.endswith(("\n", "\r")) for line in f)
> 
> # Works only on Windows text files.
> def chomp(lines):
>     for line in lines:
>         yield line.rstrip('\r\n')

.rstrip() takes a string that is a set of characters, so it will
remove any \r or \n at the end of the string (so it works with
both Windows & *nix line-endings) whereas just using .rstrip()
without a parameter can throw away data you might want:

  >>> "hello \r\n\r\r\n\n\n".rstrip("\r\n")
  'hello '
  >>> "hello \r\n\r\r\n\n\n".rstrip()
  'hello'

-tkc