我们在提取一个文件元信息的时候，经常会使用到获取元信息的size， 但是默认提取出来的是字节为单位计算的大小，我们需要转换成MB或者GB 或者TB的大小。
因此就需要使用到humansize这个模块， 这个模块不是系统内置的， 你可以通过help（）查询内置模块是没有这个的模块的。 需要从其他地方导入才可以进行使用。
将下面的文件保存成humansize.py 放在默认python目录下。
1 '''''Convert file sizes to human-readable form. 2 3 Available functions: 4 approximate_size(size, a_kilobyte_is_1024_bytes) 5 takes a file size and returns a human-readable string 6 7 Examples: 8 >>> approximate_size(1024) 9 '1.0 KiB' 10 >>> approximate_size(1000, False) 11 '1.0 KB' 12 13 ''' 14 15 SUFFIXES = {1000: ['KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'], 16 1024: ['KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB']} 17 18 def approximate_size(size, a_kilobyte_is_1024_bytes=True): 19 '''''Convert a file size to human-readable form. 20 21 Keyword arguments: 22 size -- file size in bytes 23 a_kilobyte_is_1024_bytes -- if True (default), use multiples of 1024 24 if False, use multiples of 1000 25 26 Returns: string 27 28 ''' 29 if size < 0: 30 raise ValueError('number must be non-negative') 31 32 multiple = 1024 if a_kilobyte_is_1024_bytes else 1000 33 for suffix in SUFFIXES[multiple]: 34 size /= multiple 35 if size < multiple: 36 return '{0:.1f} {1}'.format(size, suffix) 37 38 raise ValueError('number too large') 39 40 if __name__ == '__main__': 41 print(approximate_size(1000000000000, False)) 42 print(approximate_size(1000000000000)) 43 44 # Copyright (c) 2009, Mark Pilgrim, All rights reserved. 45 # 46 # Redistribution and use in source and binary forms, with or without modification, 47 # are permitted provided that the following conditions are met: 48 # 49 # * Redistributions of source code must retain the above copyright notice, 50 # this list of conditions and the following disclaimer. 51 # * Redistributions in binary form must reproduce the above copyright notice, 52 # this list of conditions and the following disclaimer in the documentation 53 # and/or other materials provided with the distribution. 54 # 55 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 'AS IS' 56 # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 59 # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 60 # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 61 # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 62 # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 63 # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 64 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 65 # POSSIBILITY OF SUCH DAMAGE.
该程序的功能是将以字节为单位的文件大小转换为以更易读形式，如将1024 B转换为1KB
1 >>> import sys 2 >>> import os 3 >>> metadata = os.stat('test.docx') 4 >>> metadata 5 nt.stat_result(st_mode=33206, st_ino=0L, st_dev=0L, st_nlink=0, st_uid=0, st_gid=0, st_size=4934265L, st_atime=1472518662L, st_mtime=1469435178L, st_ctime=1472518662L) 6 >>> metadata.st_size 7 4934265L 8 >>> import humansize 9 >>> humansize.approximate_size(metadata.st_size ) 10 '4.0 MiB' 11 >>>