我如何获得一个人类可读的文件大小字节缩写使用。net ?
例子: 输入7,326,629,显示6.98 MB
我如何获得一个人类可读的文件大小字节缩写使用。net ?
例子: 输入7,326,629,显示6.98 MB
当前回答
下面是一个Log10的方法:
using System;
class Program {
static string NumberFormat(double n) {
var n2 = (int)Math.Log10(n) / 3;
var n3 = n / Math.Pow(1e3, n2);
return String.Format("{0:f3}", n3) + new[]{"", " k", " M", " G"}[n2];
}
static void Main() {
var s = NumberFormat(9012345678);
Console.WriteLine(s == "9.012 G");
}
}
https://learn.microsoft.com/dotnet/api/system.math.log10
其他回答
请求函数的测试和显著优化版本发布在这里:
c#人类可读文件大小-优化的函数
源代码:
// Returns the human-readable file size for an arbitrary, 64-bit file size
// The default format is "0.### XB", e.g. "4.2 KB" or "1.434 GB"
public string GetBytesReadable(long i)
{
// Get absolute value
long absolute_i = (i < 0 ? -i : i);
// Determine the suffix and readable value
string suffix;
double readable;
if (absolute_i >= 0x1000000000000000) // Exabyte
{
suffix = "EB";
readable = (i >> 50);
}
else if (absolute_i >= 0x4000000000000) // Petabyte
{
suffix = "PB";
readable = (i >> 40);
}
else if (absolute_i >= 0x10000000000) // Terabyte
{
suffix = "TB";
readable = (i >> 30);
}
else if (absolute_i >= 0x40000000) // Gigabyte
{
suffix = "GB";
readable = (i >> 20);
}
else if (absolute_i >= 0x100000) // Megabyte
{
suffix = "MB";
readable = (i >> 10);
}
else if (absolute_i >= 0x400) // Kilobyte
{
suffix = "KB";
readable = i;
}
else
{
return i.ToString("0 B"); // Byte
}
// Divide by 1024 to get fractional value
readable = (readable / 1024);
// Return formatted number with suffix
return readable.ToString("0.### ") + suffix;
}
这个问题很老了,但是一个非常快速的c#函数可以是:
public static string PrettyPrintBytes(long numBytes)
{
if (numBytes < 1024)
return $"{numBytes} B";
if (numBytes < 1048576)
return $"{numBytes / 1024d:0.##} KB";
if (numBytes < 1073741824)
return $"{numBytes / 1048576d:0.##} MB";
if (numBytes < 1099511627776)
return $"{numBytes / 1073741824d:0.##} GB";
if (numBytes < 1125899906842624)
return $"{numBytes / 1099511627776d:0.##} TB";
if (numBytes < 1152921504606846976)
return $"{numBytes / 1125899906842624d:0.##} PB";
return $"{numBytes / 1152921504606846976d:0.##} EB";
}
每次调用只有一次强制转换和一次除法,最多只能进行6次比较。在进行基准测试时,我发现字符串插值比使用string . format()快得多。
这里没有什么东西完全符合我的需要,我根据这个线程制作了我自己的,所以这里是我的长扩展,允许您根据标准选择格式要求。
绝对不是最快的,但很灵活。支持EB/EiB。
// <summary>
/// <paramref name="byteCount"/> The original size in bytes ( 8 bits )
/// <paramref name="notationFormat"/> is supported in the following ways:
/// [ 'B' / 'b' : Binary : Kilobyte (KB) is 1024 bytes, Megabyte (MB) is 1048576 bytes, etc ]
/// [ 'I' / 'i' : IEC: Kibibyte (KiB) is 1024 bytes, Mebibyte (MiB) is 1048576 bytes, etc ]
/// [ 'D' / 'd' : Decimal : Kilobyte (KB) is 1000 bytes, Megabyte (MB) is 1000000 bytes, etc ]
/// </summary>
public static string ToDataSizeString( this long byteCount, char notationFormat = 'b' )
{
char[] supportedFormatChars = { 'b', 'i', 'd' };
var lowerCaseNotationFormat = char.ToLowerInvariant( notationFormat );
// Stop shooting holes in my ship!
if ( !supportedFormatChars.Contains( lowerCaseNotationFormat ) )
{
throw new ArgumentException( $"notationFormat argument '{notationFormat}' not supported" );
}
long ebLimit = 1152921504606846976;
long pbLimit = 1125899906842624;
long tbLimit = 1099511627776;
long gbLimit = 1073741824;
long mbLimit = 1048576;
long kbLimit = 1024;
var ebSuffix = "EB";
var pbSuffix = "PB";
var tbSuffix = "TB";
var gbSuffix = "GB";
var mbSuffix = "MB";
var kbSuffix = "KB";
var bSuffix = " B";
switch ( lowerCaseNotationFormat )
{
case 'b':
// Sweet as
break;
case 'i':
// Limits stay the same, suffixes need changed
ebSuffix = "EiB";
pbSuffix = "PiB";
tbSuffix = "TiB";
gbSuffix = "GiB";
mbSuffix = "MiB";
kbSuffix = "KiB";
bSuffix = " B";
break;
case 'd':
// Suffixes stay the same, limits need changed
ebLimit = 1000000000000000000;
pbLimit = 1000000000000000;
tbLimit = 1000000000000;
gbLimit = 1000000000;
mbLimit = 1000000;
kbLimit = 1000;
break;
default:
// Should have already Excepted, but hey whatever
throw new ArgumentException( $"notationFormat argument '{notationFormat}' not supported" );
}
string fileSizeText;
// Exa/Exbi sized
if ( byteCount >= ebLimit )
{
fileSizeText = $"{( (double)byteCount / ebLimit ):N1} {ebSuffix}";
}
// Peta/Pebi sized
else if ( byteCount >= pbLimit )
{
fileSizeText = $"{( (double)byteCount / pbLimit ):N1} {pbSuffix}";
}
// Tera/Tebi sized
else if ( byteCount >= tbLimit )
{
fileSizeText = $"{( (double)byteCount / tbLimit ):N1} {tbSuffix}";
}
// Giga/Gibi sized
else if ( byteCount >= gbLimit )
{
fileSizeText = $"{( (double)byteCount / gbLimit ):N1} {gbSuffix}";
}
// Mega/Mibi sized
else if ( byteCount >= mbLimit )
{
fileSizeText = $"{( (double)byteCount / mbLimit ):N1} {mbSuffix}";
}
// Kilo/Kibi sized
else if ( byteCount >= kbLimit )
{
fileSizeText = $"{( (double)byteCount / kbLimit ):N1} {kbSuffix}";
}
// Byte sized
else
{
fileSizeText = $"{byteCount} {bSuffix}";
}
return fileSizeText;
}
int size = new FileInfo( filePath ).Length / 1024;
string humanKBSize = string.Format( "{0} KB", size );
string humanMBSize = string.Format( "{0} MB", size / 1024 );
string humanGBSize = string.Format( "{0} GB", size / 1024 / 1024 );
我猜你要找的是“1.4 MB”而不是“1468006字节”?
我不认为在。net中有内置的方法来做到这一点。你只需要找出哪个单元是合适的,然后格式化它。
编辑:这里有一些示例代码来做到这一点:
http://www.codeproject.com/KB/cpp/formatsize.aspx