gzip
— 支持
gzip
文件
¶
源代码： Lib/gzip.py
This module provides a simple interface to compress and decompress files just like the GNU programs gzip and gunzip would.
The data compression is provided by the
zlib
模块。
The
gzip
module provides the
GzipFile
class which is modeled after Python’s File Object. The
GzipFile
class reads and writes
gzip
-format files, automatically compressing or decompressing the data so that it looks like an ordinary file object.
Note that additional file formats which can be decompressed by the gzip and gunzip programs, such as those produced by compress and pack , are not supported by this module.
模块定义了下列项：
gzip.
GzipFile
(
[
filename
[
,
mode
[
,
compresslevel
[
,
fileobj
[
,
mtime
]
]
]
]
]
)
¶
构造函数对于
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
，在这种情况下
filename
is opened to provide a file object.
当
fileobj
不是
None
，
filename
argument is only used to be included in the
gzip
file header, which may include 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'
，或
'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.
The
compresslevel
argument is an integer from
0
to
9
controlling the level of compression;
1
is fastest and produces the least compression, and
9
is slowest and produces the most compression.
0
is no compression. The default is
9
.
The
mtime
argument is an optional numeric timestamp to be written to the stream when compressing. All
gzip
compressed streams are required to contain a timestamp. If omitted or
None
, the current time is used. This module ignores the timestamp when decompressing; however, some programs, such as
gunzip
, make use of it. The format of the timestamp is the same as that of the return value of
time.time()
and of the
st_mtime
attribute of the object returned by
os.stat()
.
Calling a
GzipFile
对象的
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
对象的
getvalue()
方法。
GzipFile
supports iteration and the
with
语句。
2.7 版改变：
支持
with
语句被添加。
2.7 版改变： Support for zero-padded files was added.
New in version 2.7: The mtime 自变量。
gzip.
open
(
filename
[
,
mode
[
,
compresslevel
]
]
)
¶
这是简写的
GzipFile(filename,
mode,
compresslevel)
。
filename
argument is required;
mode
默认为
'rb'
and
compresslevel
默认为
9
.
Example of how to read a compressed file:
import gzip with gzip.open('file.txt.gz', 'rb') as f: file_content = f.read()
Example of how to create a compressed GZIP file:
import gzip content = "Lots of content here" with gzip.open('file.txt.gz', 'wb') as f: f.write(content)
Example of how to GZIP compress an existing file:
import gzip import shutil with open('file.txt', 'rb') as f_in, gzip.open('file.txt.gz', 'wb') as f_out: shutil.copyfileobj(f_in, f_out)
另请参阅
zlib
The basic data compression module needed to support the gzip 文件格式。