byte[] to hex string [duplicate]

Answer 1

With:

byte[] data = new byte[] { 0x01, 0x02, 0x03, 0x0D, 0x0E, 0x0F };
string hex = string.Empty;
data.ToList().ForEach(b => hex += b.ToString("x2"));
// use "X2" for uppercase hex letters
Console.WriteLine(hex);

Result: 0102030d0e0f

Answer 2

Very fast extension methods (with reversal):

public static class ExtensionMethods {
    public static string ToHex(this byte[] data) {
        return ToHex(data, "");
    }
    public static string ToHex(this byte[] data, string prefix) {
        char[] lookup = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
        int i = 0, p = prefix.Length, l = data.Length;
        char[] c = new char[l * 2 + p];
        byte d;
        for(; i < p; ++i) c[i] = prefix[i];
        i = -1;
        --l;
        --p;
        while(i < l) {
            d = data[++i];
            c[++p] = lookup[d >> 4];
            c[++p] = lookup[d & 0xF];
        }
        return new string(c, 0, c.Length);
    }
    public static byte[] FromHex(this string str) {
        return FromHex(str, 0, 0, 0);
    }
    public static byte[] FromHex(this string str, int offset, int step) {
        return FromHex(str, offset, step, 0);
    }
    public static byte[] FromHex(this string str, int offset, int step, int tail) {
        byte[] b = new byte[(str.Length - offset - tail + step) / (2 + step)];
        byte c1, c2;
        int l = str.Length - tail;
        int s = step + 1;
        for(int y = 0, x = offset; x < l; ++y, x += s) {
            c1 = (byte)str[x];
            if(c1 > 0x60) c1 -= 0x57;
            else if(c1 > 0x40) c1 -= 0x37;
            else c1 -= 0x30;
            c2 = (byte)str[++x];
            if(c2 > 0x60) c2 -= 0x57;
            else if(c2 > 0x40) c2 -= 0x37;
            else c2 -= 0x30;
            b[y] = (byte)((c1 << 4) + c2);
        }
        return b;
    }
}

Beats all the others in the speed test above:

=== Long string test
BitConvertReplace calculation Time Elapsed 2415 ms
StringBuilder calculation Time Elapsed 5668 ms
LinqConcat calculation Time Elapsed 11826 ms
LinqJoin calculation Time Elapsed 9323 ms
LinqAgg calculation Time Elapsed 7444 ms
ToHexTable calculation Time Elapsed 1028 ms
ToHexAcidzombie calculation Time Elapsed 1035 ms
ToHexPatrick calculation Time Elapsed 814 ms
ToHexKurt calculation Time Elapsed 1604 ms
ByteArrayToHexString calculation Time Elapsed 1330 ms

=== Many string test
BitConvertReplace calculation Time Elapsed 2238 ms
StringBuilder calculation Time Elapsed 5393 ms
LinqConcat calculation Time Elapsed 9043 ms
LinqJoin calculation Time Elapsed 9131 ms
LinqAgg calculation Time Elapsed 7324 ms
ToHexTable calculation Time Elapsed 968 ms
ToHexAcidzombie calculation Time Elapsed 969 ms
ToHexPatrick calculation Time Elapsed 956 ms
ToHexKurt calculation Time Elapsed 1547 ms
ByteArrayToHexString calculation Time Elapsed 1277 ms

Answer 3

Just to add one more answer to the pile, there is a System.Runtime.Remoting.Metadata.W3cXsd2001.SoapHexBinary class that I've used which can convert bytes to and from hex:

string hex = new SoapHexBinary(bytes).ToString();
byte[] bytes = SoapHexBinary.Parse(hex).Value;

Not sure how it compares (benchmark) to other implementations, but IMO it is pretty simple -- especially for converting from hex back into bytes.

Answer 4

I thought I should provide an answer. From my test this method is the fastest

public static class Helper
{
    public static string[] HexTbl = Enumerable.Range(0, 256).Select(v => v.ToString("X2")).ToArray();
    public static string ToHex(this IEnumerable<byte> array)
    {
        StringBuilder s = new StringBuilder();
        foreach (var v in array)
            s.Append(HexTbl[v]);
        return s.ToString();
    }
    public static string ToHex(this byte[] array)
    {
        StringBuilder s = new StringBuilder(array.Length*2);
        foreach (var v in array)
            s.Append(HexTbl[v]);
        return s.ToString();
    }
}

Answer 5

Well I don't convert bytes to hex often so I have to say I don't know if there is a better way then this, but here is a way to do it.

StringBuilder sb = new StringBuilder();
foreach (byte b in myByteArray)
    sb.Append(b.ToString("X2"));

string hexString = sb.ToString();

Answer 6

Nice way to do this with LINQ...

var data = new byte[] { 1, 2, 4, 8, 16, 32 }; 
var hexString = data.Aggregate(new StringBuilder(), 
                               (sb,v)=>sb.Append(v.ToString("X2"))
                              ).ToString();