La compresión de datos proporcionada por el módulo zlib
es compatible con la utilizada por el compresor de GNU, gzip.
Además, el módulo gzip proporciona la clase GzipFile
para leer y escribir ficheros de formato gzip, comprimiendo y
descomprimiendo transparentemente los datos para que los ficheros parezcan
normales (sin comprimir). Hay que destacar que otros formatos de compresión que
los programas gzip y gunzip manejan perfectamente no están
dentro de los gestionados por esta biblioteca. En concreto, este programa no
gestiona los formatos producidos por compress ni pack.
Este módule define los siguientes elementos:
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.
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.
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'
.
Be aware that only the 'rb'
, 'ab'
, and 'wb'
values should be used for cross-platform portability.
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.
GzipFile(filename,
mode,
compresslevel)
. The filename
argument is required; mode defaults to 'rb'
and
compresslevel defaults to 9
.
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