Python doc problems example: gzip module

[Xah Lee]

Today i need to use Python to compress/decompress gzip files.

I quickly found the official doc:
http://python.org/doc/2.4.1/lib/module-gzip.html

I'd imagine it being a function something like
GzipFile(filePath, comprress/decompress, outputPath)

however, scanning the doc after 20 seconds there's no single example
showing how it is used.

Instead, the doc starts with some arcane info about compatibility with
some zlib module and other software.

Then it talks in a very big computer sciency way with bad writing about
the main function GzipFile. No perspectives whatsoever about using it
to solve a problem nor a concrete description of how it functions.
Instead, jargons of Class, Constructor, Object etc are thrown together
with presumption of reader's expertise of Python's file objects and
gzip technical details.

after no understanding, and being not a Python expert, i wanted to read
about file objects but there's no link.

after locating the file object doc page
http://python.org/doc/2.4.1/lib/bltin-file-objects.html
itself talks in some obfuscated incomprehensible way.

---------------
Here's the detail of the GzipFile description:

class GzipFile(	[filename[, mode[, compresslevel[, fileobj]]]])
Constructor for the GzipFile class, which simulates most of the methods
of a file object, with the exception of the readinto() and truncate()
methods. At least one of fileobj and filename must be given a
non-trivial value.
The new class instance is based on fileobj, which can be a regular
file, a StringIO object, or any other object which simulates a file. It
defaults to None, in which case filename is opened to provide a file
object.

 yeah, blab blab blab. what the fuck are you talking about? So, how to
use it?

When fileobj is not None, the filename argument is only used to be
included in the gzip file header, which may includes the original
filename of the uncompressed file. It defaults to the filename of
fileobj, if discernible; otherwise, it defaults to the empty string,
and in this case the original filename is not included in the header.

 what the fuck??

The mode argument can be any of 'r', 'rb', 'a', 'ab', 'w', or 'wb',
depending on whether the file will be read or written. The default is
the mode of fileobj if discernible; otherwise, the default is 'rb'. If
not given, the 'b' flag will be added to the mode to ensure the file is
opened in binary mode for cross-platform portability.

 discernible? so, what the fuck are exactly these modes? can't you
describe them concretely?

The compresslevel argument is an integer from 1 to 9 controlling the
level of compression; 1 is fastest and produces the least compression,
and 9 is slowest and produces the most compression. The default is 9.

Calling a GzipFile object's close() method does not close fileobj,
since you might wish to append more material after the compressed data.
This also allows you to pass a StringIO object opened for writing as
fileobj, and retrieve the resulting memory buffer using the StringIO
object's getvalue() method.

  huh? append more material? pass a StringIO? and memory buffer?

--------------------
Motherfucking 90% of programers using this module really just want to
compress or decompress a file.

Fuck unix advocates and fuck Perlers and fuck Python morons.

PS For more about Python doc, please see:
http://xahlee.org/perl-python/re-write_notes.html

 Xah
 xah at xahlee.org
∑ http://xahlee.org/