在Python中稀疏文件的使用 [英] sparse file usage in python
问题描述
我在python中创建稀疏文件如下:
>>> f = open('testfile','ab')
>>> f.truncate(1024000)
>>> f.close()
当文件完成时,占用0个磁盘空间,但其inode大小设置为我截断的值(1000K):
$ $ p $ igor47 @ piglet:〜/ test $ ls -lh testfile
-rw -r -r-1 igor47 igor47 1000K 2010-07-09 04:02 testfile
igor47 @ piglet:〜/ test $ du -hs testfile
0 testfile
如何在python中获取文件的实际空间使用情况? stat
调用返回文件的外观大小,我不知道除了读整个文件外, p>
>>> os.stat('testfile')。st_size
1024000
>>> os.stat('testfile')。st_blocks * 512
0
Tadaa:)
st_blocks
是实际分配给文件的512字节块的数量。请注意, st_blocks
不能保证在所有的操作系统中都存在,但是那些支持稀疏文件的文件通常是这样。
I'm creating sparse files in python as follows:
>>> f = open('testfile', 'ab')
>>> f.truncate(1024000)
>>> f.close()
when the file is done, it takes up 0 disk space, but its inode size is set to my truncated value (1000K):
igor47@piglet:~/test$ ls -lh testfile
-rw-r--r-- 1 igor47 igor47 1000K 2010-07-09 04:02 testfile
igor47@piglet:~/test$ du -hs testfile
0 testfile
how do i get the file's real space usage inside python? the stat
call returns the file's apparent size, and i have no idea how else to get the real usage other than to read the entire file (it may become quite large)
>>> os.stat('testfile').st_size
1024000
>>> os.stat('testfile').st_blocks*512
0
Tadaa :)
st_blocks
is the number of 512-byte blocks actually allocated to the file. Note that st_blocks
is not guaranteed to be present in all operating systems, but those that support sparse files generally do.
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