从字节大小返回人类可读大小的函数:
>>> human_readable(2048)
'2 kilobytes'
>>>
如何做到这一点?
从字节大小返回人类可读大小的函数:
>>> human_readable(2048)
'2 kilobytes'
>>>
如何做到这一点?
当前回答
参考Sridhar Ratnakumar的回答,更新为:
def formatSize(sizeInBytes, decimalNum=1, isUnitWithI=False, sizeUnitSeperator=""):
"""format size to human readable string"""
# https://en.wikipedia.org/wiki/Binary_prefix#Specific_units_of_IEC_60027-2_A.2_and_ISO.2FIEC_80000
# K=kilo, M=mega, G=giga, T=tera, P=peta, E=exa, Z=zetta, Y=yotta
sizeUnitList = ['','K','M','G','T','P','E','Z']
largestUnit = 'Y'
if isUnitWithI:
sizeUnitListWithI = []
for curIdx, eachUnit in enumerate(sizeUnitList):
unitWithI = eachUnit
if curIdx >= 1:
unitWithI += 'i'
sizeUnitListWithI.append(unitWithI)
# sizeUnitListWithI = ['','Ki','Mi','Gi','Ti','Pi','Ei','Zi']
sizeUnitList = sizeUnitListWithI
largestUnit += 'i'
suffix = "B"
decimalFormat = "." + str(decimalNum) + "f" # ".1f"
finalFormat = "%" + decimalFormat + sizeUnitSeperator + "%s%s" # "%.1f%s%s"
sizeNum = sizeInBytes
for sizeUnit in sizeUnitList:
if abs(sizeNum) < 1024.0:
return finalFormat % (sizeNum, sizeUnit, suffix)
sizeNum /= 1024.0
return finalFormat % (sizeNum, largestUnit, suffix)
示例输出如下:
def testKb():
kbSize = 3746
kbStr = formatSize(kbSize)
print("%s -> %s" % (kbSize, kbStr))
def testI():
iSize = 87533
iStr = formatSize(iSize, isUnitWithI=True)
print("%s -> %s" % (iSize, iStr))
def testSeparator():
seperatorSize = 98654
seperatorStr = formatSize(seperatorSize, sizeUnitSeperator=" ")
print("%s -> %s" % (seperatorSize, seperatorStr))
def testBytes():
bytesSize = 352
bytesStr = formatSize(bytesSize)
print("%s -> %s" % (bytesSize, bytesStr))
def testMb():
mbSize = 76383285
mbStr = formatSize(mbSize, decimalNum=2)
print("%s -> %s" % (mbSize, mbStr))
def testTb():
tbSize = 763832854988542
tbStr = formatSize(tbSize, decimalNum=2)
print("%s -> %s" % (tbSize, tbStr))
def testPb():
pbSize = 763832854988542665
pbStr = formatSize(pbSize, decimalNum=4)
print("%s -> %s" % (pbSize, pbStr))
def demoFormatSize():
testKb()
testI()
testSeparator()
testBytes()
testMb()
testTb()
testPb()
# 3746 -> 3.7KB
# 87533 -> 85.5KiB
# 98654 -> 96.3 KB
# 352 -> 352.0B
# 76383285 -> 72.84MB
# 763832854988542 -> 694.70TB
# 763832854988542665 -> 678.4199PB
其他回答
使用1000或kibibytes的幂将更符合标准:
def sizeof_fmt(num, use_kibibyte=True):
base, suffix = [(1000.,'B'),(1024.,'iB')][use_kibibyte]
for x in ['B'] + map(lambda x: x+suffix, list('kMGTP')):
if -base < num < base:
return "%3.1f %s" % (num, x)
num /= base
return "%3.1f %s" % (num, x)
附注:永远不要相信一个以K(大写)后缀打印数千的库。
如果有人想知道,要将@Sridhar Ratnakumar的答案转换回字节,您可以执行以下操作:
import math
def format_back_to_bytes(value):
for power, unit in enumerate(["", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi"]):
if value[-3:-1] == unit:
return round(float(value[:-3])*math.pow(2, 10*power))
用法:
>>> format_back_to_bytes('212.4GiB')
228062763418
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'
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]
简单的两行字怎么样:
def humanizeFileSize(filesize):
p = int(math.floor(math.log(filesize, 2)/10))
return "%.3f%s" % (filesize/math.pow(1024,p), ['B','KiB','MiB','GiB','TiB','PiB','EiB','ZiB','YiB'][p])
下面是它的工作原理:
计算log2(文件大小) 除以10得到最接近的单位。(例如,如果大小是5000字节,最接近的单位是Kb,所以答案应该是X KiB) 返回file_size/value_of_closest_unit和unit。
然而,如果filesize为0或负(因为log对于0和-ve数字是未定义的),它就不起作用。你可以为他们添加额外的检查:
def humanizeFileSize(filesize):
filesize = abs(filesize)
if (filesize==0):
return "0 Bytes"
p = int(math.floor(math.log(filesize, 2)/10))
return "%0.2f %s" % (filesize/math.pow(1024,p), ['Bytes','KiB','MiB','GiB','TiB','PiB','EiB','ZiB','YiB'][p])
例子:
>>> humanizeFileSize(538244835492574234)
'478.06 PiB'
>>> humanizeFileSize(-924372537)
'881.55 MiB'
>>> humanizeFileSize(0)
'0 Bytes'
—Kb与KiB有区别。KB表示1000字节,而KiB表示1024字节。KB、MB、GB都是1000的倍数,KiB、MiB、GiB等都是1024的倍数。更多信息请点击这里