Nubie question: how to not pass "self" in call to seek() function ?

[Mark Tolonen]

"Barak, Ron" <Ron.Barak at lsi.com> wrote in message 
news:7F0503CD69378F49BE0DC30661C6CCF602494BA6 at enbmail01.lsi.com...
> Hi,
>
> I am getting the error TypeError: seek() takes exactly 2 arguments (3 
> given), namely:
>
> $ ./_LogStream.py
> Traceback (most recent call last):
>   File "./_LogStream.py", line 47, in <module>
>     log_stream.last_line_loc_and_contents()
>   File "./_LogStream.py", line 20, in last_line_loc_and_contents
>     self.input_file.seek(-1, 2) # grab the last character
> TypeError: seek() takes exactly 2 arguments (3 given)
>
> When I run the below code.
>
> I understand that the extra argument is the "self", but I don't know how 
> to change my class to make the seek(-1,2) work.
>
> Could you help ?

Perhaps the extra agrument is 2.  You don't mention your Python version, but 
in Python 2.6.1 gzip files don't support seeking from the end.  An older 
(your?) version of Python may not be providing as helpful an error message.

>>> f=gzip.GzipFile('blah.gz','r')
>>> f.seek(-1,2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\dev\python\lib\gzip.py", line 368, in seek
    raise ValueError('Seek from end not supported')
ValueError: Seek from end not supported

-Mark


>
> Thanks,
> Ron.
>
> $ cat _LogStream.py
> #!/usr/bin/env python
>
> import gzip
> import sys
>
> from Debug import _line as line
>
> class LogStream():
>
>     def __init__(self, filename):
>         self.filename = filename
>         self.input_file = self.open_file(filename)
>         self.index_increment = 10
>         self.last_line_offset = -1
>
>     def last_line_loc_and_contents(self, estimated_line_size=1024):
>
>         assert estimated_line_size > 0
>         file_size = len(self.input_file.read())
>         self.input_file.seek(-1, 2) # grab the last character
>
>         if self.input_file.read(1) == '\n': # a "proper" text file
>             file_size -= 1
>
>     def open_file(self, in_file):
>         """
>         The gzip module checks if the input file is a gzipped file, only 
> at the read stage.
>         This is why the f.readline() is needed.
>         """
>         try:
>             f = gzip.GzipFile(in_file, "r")
>             f.readline()
>         except IOError:
>             f = open(in_file, "r")
>             f.readline()
>
>         f.seek(0)
>         return(f)
>
>
> if __name__ == "__main__":
>     filename = 
> "../save_state/hp/save_state-ssp8400-0709R00004_081126-121659/var/log\\sac.log.4.gz"
>     log_stream = LogStream(filename)
>     log_stream.limit_ = 1000
>     log_stream.index_increment = 12
>
>     log_stream.last_line_loc_and_contents()




--
http://mail.python.org/mailman/listinfo/python-list