Convert a string into a byte array in c#

Question

I have a string,

string Var="11001100"

I want to convert it into a byte array.

bArray[0]=0x00;
bArray[1]=0x00;
bArray[2]=0x01;
bArray[3]=0x01;
bArray[4]=0x00;
bArray[5]=0x00;
bArray[6]=0x01;
bArray[7]=0x01;

Can anybody guide me in this? I tried the following code, but I get the data in ASCII. I do not want that.

bArray = Encoding.Default.GetBytes(var);

Possible duplicate of [Converting string to byte array in C#](https://stackoverflow.com/questions/16072709/converting-string-to-byte-array-in-c-sharp) — FakeCaleb, Aug 18 '17 at 08:30
I want byte array only.I tried that Encoding.ASCII.GetBytes(var); I do not want the data in acii i.e 48 for 0 and so on. I want to retain the binary string. — k11, Aug 18 '17 at 08:32
or you could do ascii arithmetics and subtract the ascii value of '0', which is 48 — Cee McSharpface, Aug 18 '17 at 08:32
@FakeCaleb it's not a duplicate I think actually. Try to see Dmitry's answer. — Mathias Lykkegaard Lorenzen, Aug 18 '17 at 08:33
@MathiasLykkegaardLorenzen Now I've seen OPs comment you maybe right, but it wasn't clear (even now) what he actually meant — FakeCaleb, Aug 18 '17 at 08:36
that duplicate has an *answer* that answers *this*, but not the duplicate question itself... the desired output is the OP second code section — Cee McSharpface, Aug 18 '17 at 08:36
what would be the outcome for this input: `string Var="10101100";` ? — Mong Zhu, Aug 18 '17 at 08:54

Dmitry Bychenko · Answer 1 · 2017-08-18T08:38:19.810

I suggest using Linq:

using System.Linq;

...

string Var = "11001100";

byte[] bArray = Var
  .Select(item => (byte) (item == '0' ? 1 : 0))
  .ToArray();

Test:

Console.WriteLine(string.Join(Environment.NewLine, bArray
  .Select((value, index) => $"bArray[{index}]=0x{value:X2};")));

Outcome:

bArray[0]=0x00;
bArray[1]=0x00;
bArray[2]=0x01;
bArray[3]=0x01;
bArray[4]=0x00;
bArray[5]=0x00;
bArray[6]=0x01;
bArray[7]=0x01;

Mong Zhu · Answer 2 · 2017-08-18T08:47:57.707

1

but I get the data in ASCII. I do not want that.

Then you need the string representation of the chars. You get it using the ToString method. This would be the old scool way simply using a reversed for-loop:

string Var="11001100";

byte [] bArray = new byte[Var.Length];

int countForward = 0;
for (int i = Var.Length-1; i >= 0 ; i--)
{
    bArray[countForward] = Convert.ToByte(Var[i].ToString());
    countForward++;
}

edited Aug 18 '17 at 08:47

answered Aug 18 '17 at 08:41

Mong Zhu

23,309
10
44
76

Please notice, that `bArray` should contain *inversed* values: `'1' -> 0` and `'0' -> 1` – Dmitry Bychenko Aug 18 '17 at 08:44
@DmitryBychenko I have the feeling that OP is reading the input from right to left (little endian fashion). Therefore I chose the reversed for loop – Mong Zhu Aug 18 '17 at 08:47
I see; we need a better test example to distinguish between these two possibilities... – Dmitry Bychenko Aug 18 '17 at 08:49
@DmitryBychenko lets see whether he answers my question from the comment – Mong Zhu Aug 18 '17 at 08:50
well, in case of, say, `"11010101"` the outcomes are *different*: `[0, 0, 1, 0, 1, 0, 1, 0]` (my understanding - bytes reversing) and `[0, 1, 0, 1, 0, 1, 0, 0]` (your reading - little/big endian). The test case provided `"11001100"` can't help to chose the right one (alas!) – Dmitry Bychenko Aug 18 '17 at 08:57
@DmitryBychenko I agree, same holds for the test case from my comment. Lets wait and see what and if OP responds to my comment – Mong Zhu Aug 18 '17 at 09:12

Sebastian Richter · Answer 3 · 2017-08-18T08:52:40.620

0

This is my solution for your question:

string value = "11001100";
int numberOfBits = value.Length;
var valueAsByteArray = new byte[numberOfBits];

for (int i = 0; i < numberOfBits; i++)
{
    bytes[i] = ((byte)(value[i] - 0x30)) == 0 ? (byte)1 : (byte)0;
}

Edit: Forgot the inversion.

edited Aug 18 '17 at 08:52

answered Aug 18 '17 at 08:41

Sebastian Richter

477
8
18

Convert a string into a byte array in c#

3 Answers3