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Groups > comp.lang.python > #9342

Re: How to write a file generator

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On 07/12/2011 06:42 PM, Billy Mays wrote:
> On 07/12/2011 11:52 AM, Thomas Jollans wrote:
>> On 07/12/2011 04:46 PM, Billy Mays wrote:
>>> I want to make a generator that will return lines from the tail of
>>> /var/log/syslog if there are any, but my function is reopening the file
>>> each call:
>>>
>>> def getLines():
>>>      with open('/var/log/syslog', 'rb') as f:
>>>          while True:
>>>              line = f.readline()
>>>              if line:
>>>                  yield line
>>>              else:
>>>                  raise StopIteration
>>>
>>>
>>> I know the problem lies with the StopIteration, but I'm not sure how to
>>> tell the caller that there are no more lines for now.
>>>
>>> -- 
>>> Bill
>>
>> http://stackoverflow.com/questions/1475950/tail-f-in-python-with-no-time-sleep
>>
> 
> 
> That was actually the behavior I was trying to avoid.  If there is no
> data to be read, the call will hang.  That function is actually called
> by a webserver (from wsgiref) so it cannot hang indefinitely.


What Terry said, then. (Not Bruno, I confused that. Sorry for sending a
mail both short and wrong.)

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Thread

How to write a file generator Billy Mays <noway@nohow.com> - 2011-07-12 10:46 -0400
  Re: How to write a file generator "bruno.desthuilliers@gmail.com" <bruno.desthuilliers@gmail.com> - 2011-07-12 08:34 -0700
  Re: How to write a file generator Thomas Jollans <t@jollybox.de> - 2011-07-12 17:52 +0200
    Re: How to write a file generator Billy Mays <noway@nohow.com> - 2011-07-12 12:42 -0400
      Re: How to write a file generator Thomas Jollans <t@jollybox.de> - 2011-07-12 21:04 +0200
      Re: How to write a file generator Thomas Jollans <t@jollybox.de> - 2011-07-12 21:05 +0200
  Re: How to write a file generator sturlamolden <sturlamolden@yahoo.no> - 2011-07-12 09:53 -0700
  Re: How to write a file generator Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2011-07-13 01:26 +0200

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