这是我的版本。它不使用for循环。它具有常数复杂度O(1)，理论上比这里使用for循环的答案更有效。

from math import log
unit_list = zip(['bytes', 'kB', 'MB', 'GB', 'TB', 'PB'], [0, 0, 1, 2, 2, 2])
def sizeof_fmt(num):
    """Human friendly file size"""
    if num > 1:
        exponent = min(int(log(num, 1024)), len(unit_list) - 1)
        quotient = float(num) / 1024**exponent
        unit, num_decimals = unit_list[exponent]
        format_string = '{:.%sf} {}' % (num_decimals)
        return format_string.format(quotient, unit)
    if num == 0:
        return '0 bytes'
    if num == 1:
        return '1 byte'

为了更清楚地说明发生了什么，我们可以省略字符串格式化的代码。以下是真正起作用的台词:

exponent = int(log(num, 1024))
quotient = num / 1024**exponent
unit_list[exponent]

这个解决方案可能也会吸引你，这取决于你的思维方式:

from pathlib import Path    

def get_size(path = Path('.')):
    """ Gets file size, or total directory size """
    if path.is_file():
        size = path.stat().st_size
    elif path.is_dir():
        size = sum(file.stat().st_size for file in path.glob('*.*'))
    return size

def format_size(path, unit="MB"):
    """ Converts integers to common size units used in computing """
    bit_shift = {"B": 0,
            "kb": 7,
            "KB": 10,
            "mb": 17,
            "MB": 20,
            "gb": 27,
            "GB": 30,
            "TB": 40,}
    return "{:,.0f}".format(get_size(path) / float(1 << bit_shift[unit])) + " " + unit

# Tests and test results
>>> get_size("d:\\media\\bags of fun.avi")
'38 MB'
>>> get_size("d:\\media\\bags of fun.avi","KB")
'38,763 KB'
>>> get_size("d:\\media\\bags of fun.avi","kb")
'310,104 kb'

一个拥有你所寻找的所有功能的库似乎是人性化的。Humanize.naturalsize()似乎可以做您所寻找的所有事情。

示例代码(python 3.10)

import humanize

disk_sizes_list = [1, 100, 999, 1000,1024, 2000,2048, 3000, 9999, 10000, 2048000000, 9990000000, 9000000000000000000000]
for size in disk_sizes_list:
    natural_size = humanize.naturalsize(size)
    binary_size = humanize.naturalsize(size, binary=True)
    print(f" {natural_size} \t| {binary_size}\t|{size}")

输出

 1 Byte     | 1 Byte    |1
 100 Bytes  | 100 Bytes |100
 999 Bytes  | 999 Bytes |999
 1.0 kB     | 1000 Bytes    |1000
 1.0 kB     | 1.0 KiB   |1024
 2.0 kB     | 2.0 KiB   |2000
 2.0 kB     | 2.0 KiB   |2048
 3.0 kB     | 2.9 KiB   |3000
 10.0 kB    | 9.8 KiB   |9999
 10.0 kB    | 9.8 KiB   |10000
 2.0 GB     | 1.9 GiB   |2048000000
 10.0 GB    | 9.3 GiB   |9990000000
 9.0 ZB     | 7.6 ZiB   |9000000000000000000000

你应该用humanize。

>>> humanize.naturalsize(1000000)
'1.0 MB'
>>> humanize.naturalsize(1000000, binary=True)
'976.6 KiB'
>>> humanize.naturalsize(1000000, gnu=True)
'976.6K'

参考: https://pypi.org/project/humanize/

该功能在Boltons中可用，这对于大多数项目来说都是一个非常方便的库。

>>> bytes2human(128991)
'126K'
>>> bytes2human(100001221)
'95M'
>>> bytes2human(0, 2)
'0.00B'

为了以人类可读的形式获取文件大小，我创建了这个函数:

import os

def get_size(path):
    size = os.path.getsize(path)
    if size < 1024:
        return f"{size} bytes"
    elif size < pow(1024,2):
        return f"{round(size/1024, 2)} KB"
    elif size < pow(1024,3):
        return f"{round(size/(pow(1024,2)), 2)} MB"
    elif size < pow(1024,4):
        return f"{round(size/(pow(1024,3)), 2)} GB"

>>> get_size("a.txt")
1.4KB