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, as well as the
open()
,
compress()
and
decompress()
convenience functions. The
GzipFile
class reads and writes
gzip
-format files, automatically compressing or decompressing the data so that it looks like an ordinary
文件对象
.
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.
open
(
filename
,
mode='rb'
,
compresslevel=9
,
encoding=None
,
errors=None
,
newline=None
)
¶
Open a gzip-compressed file in binary or text mode, returning a 文件对象 .
The
filename
argument can be an actual filename (a
str
or
bytes
object), or an existing file object to read from or write to.
The
mode
argument can be any of
'r'
,
'rb'
,
'a'
,
'ab'
,
'w'
,
'wb'
,
'x'
or
'xb'
对于二进制模式，或
'rt'
,
'at'
,
'wt'
，或
'xt'
for text mode. The default is
'rb'
.
The
compresslevel
argument is an integer from 0 to 9, as for the
GzipFile
构造函数。
For binary mode, this function is equivalent to the
GzipFile
构造函数：
GzipFile(filename, mode, compresslevel)
。在此情况下，
encoding
,
errors
and
newline
arguments must not be provided.
对于文本模式，
GzipFile
object is created, and wrapped in an
io.TextIOWrapper
instance with the specified encoding, error handling behavior, and line ending(s).
3.3 版改变： 添加支持 filename being a file object, support for text mode, and the encoding , errors and newline 自变量。
3.4 版改变：
添加支持
'x'
,
'xb'
and
'xt'
模式。
gzip.
GzipFile
(
filename=None
,
mode=None
,
compresslevel=9
,
fileobj=None
,
mtime=None
)
¶
构造函数对于
GzipFile
class, which simulates most of the methods of a
文件对象
, with the exception of the
truncate()
method. 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, an
io.BytesIO
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'
,
'wb'
,
'x'
，或
'xb'
, depending on whether the file will be read or written. The default is the mode of
fileobj
if discernible; otherwise, the default is
'rb'
.
Note that the file is always opened in binary mode. To open a compressed file in text mode, use
open()
(or wrap your
GzipFile
with an
io.TextIOWrapper
).
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 an
io.BytesIO
object opened for writing as
fileobj
, and retrieve the resulting memory buffer using the
io.BytesIO
对象的
getvalue()
方法。
GzipFile
支持
io.BufferedIOBase
interface, including iteration and the
with
statement. Only the
truncate()
method isn’t implemented.
GzipFile
also provides the following method:
peek
(
[
n
]
)
¶
读取 n uncompressed bytes without advancing the file position. At most one single read on the compressed stream is done to satisfy the call. The number of bytes returned may be more or less than requested.
注意
While calling
peek()
does not change the file position of the
GzipFile
, it may change the position of the underlying file object (e.g. if the
GzipFile
was constructed with the
fileobj
parameter).
3.2 版新增。
3.1 版改变：
支持
with
statement was added, along with the
mtime
自变量。
3.2 版改变： Support for zero-padded and unseekable files was added.
3.3 版改变：
The
io.BufferedIOBase.read1()
method is now implemented.
3.4 版改变：
添加支持
'x'
and
'xb'
模式。
gzip.
compress
(
data
,
compresslevel=9
)
¶
压缩
data
，返回
bytes
object containing the compressed data.
compresslevel
has the same meaning as in the
GzipFile
constructor above.
3.2 版新增。
Example of how to read a compressed file:
import gzip with gzip.open('/home/joe/file.txt.gz', 'rb') as f: file_content = f.read()
Example of how to create a compressed GZIP file:
import gzip content = b"Lots of content here" with gzip.open('/home/joe/file.txt.gz', 'wb') as f: f.write(content)
Example of how to GZIP compress an existing file:
import gzip with open('/home/joe/file.txt', 'rb') as f_in: with gzip.open('/home/joe/file.txt.gz', 'wb') as f_out: f_out.writelines(f_in)
Example of how to GZIP compress a binary string:
import gzip s_in = b"Lots of content here" s_out = gzip.compress(s_in)
另请参阅
zlib