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@ deepe1的BigInteger版本的答案,它绕过了long的大小限制(因此支持yottabyte和理论上的任何后面的限制):
public static string ToBytesString(this BigInteger byteCount, string format = "N3")
{
string[] suf = { "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "YiB" };
if (byteCount.IsZero)
{
return $"{0.0.ToString(format)} {suf[0]}";
}
var abs = BigInteger.Abs(byteCount);
var place = Convert.ToInt32(Math.Floor(BigInteger.Log(abs, 1024)));
var pow = Math.Pow(1024, place);
// since we need to do this with integer math, get the quotient and remainder
var quotient = BigInteger.DivRem(abs, new BigInteger(pow), out var remainder);
// convert the remainder to a ratio and add both back together as doubles
var num = byteCount.Sign * (Math.Floor((double)quotient) + ((double)remainder / pow));
return $"{num.ToString(format)} {suf[place]}";
}
其他回答
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。
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
另一种皮肤的方法,没有任何类型的循环和负大小支持(对文件大小增量有意义):
public static class Format
{
static string[] sizeSuffixes = {
"B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" };
public static string ByteSize(long size)
{
Debug.Assert(sizeSuffixes.Length > 0);
const string formatTemplate = "{0}{1:0.#} {2}";
if (size == 0)
{
return string.Format(formatTemplate, null, 0, sizeSuffixes[0]);
}
var absSize = Math.Abs((double)size);
var fpPower = Math.Log(absSize, 1000);
var intPower = (int)fpPower;
var iUnit = intPower >= sizeSuffixes.Length
? sizeSuffixes.Length - 1
: intPower;
var normSize = absSize / Math.Pow(1000, iUnit);
return string.Format(
formatTemplate,
size < 0 ? "-" : null, normSize, sizeSuffixes[iUnit]);
}
}
下面是测试套件:
[TestFixture] public class ByteSize
{
[TestCase(0, Result="0 B")]
[TestCase(1, Result = "1 B")]
[TestCase(1000, Result = "1 KB")]
[TestCase(1500000, Result = "1.5 MB")]
[TestCase(-1000, Result = "-1 KB")]
[TestCase(int.MaxValue, Result = "2.1 GB")]
[TestCase(int.MinValue, Result = "-2.1 GB")]
[TestCase(long.MaxValue, Result = "9.2 EB")]
[TestCase(long.MinValue, Result = "-9.2 EB")]
public string Format_byte_size(long size)
{
return Format.ByteSize(size);
}
}
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