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Re: How to write a file generator

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Am 12.07.2011 16:46 schrieb Billy Mays:
> 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

...

I have another solution: an object which is not an iterator, but an 
iterable.

class Follower(object):
     def __init__(self, file):
         self.file = file
     def __iter__(self):
         while True:
             l = self.file.readline()
             if not l: return
             yield l

if __name__ == '__main__':
     f = Follower(open("/var/log/messages"))
     while True:
         for i in f: print i,
         print "foo"
         import time
         time.sleep(4)

Here, you iterate over the object until it is exhausted, but you can 
iterate again to get the next entries.


Thomas

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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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