Converting a string of numbers to a byte array, keeping their display value.

Question

My application gets data from a hardware device which is represented as a string, EG XYZ*012. I split the string up so I get “012” which I need to convert to an array of bytes.

The problem I have is that I want each digit to keep its value so the character “0” will be stored in a byte as 0 and character “1” will be stored in the byte as 1 etc. This is required because I need to work on the bits of the bytes. I’ve tried using the “GetBytes” command but it converts “0” into 48 which is not what I want.

Is there a command to do what I want or do I need to manually handle each character in the string separately in a loop?

@Rubens: Pheew. Always use/say: subtract '0' from each (char) value. — Henk Holterman
– Henk Holterman, Commented Jul 29, 2011 at 9:35

Tim Lloyd · Accepted Answer · 2011-07-30 08:10:46Z

3

The following will normalize text character numbers, to their byte number equivalents:

byte[] bytes = data.Select(c => (byte)(c - '0')).ToArray();

edited Jul 30, 2011 at 8:10

answered Jul 29, 2011 at 9:37

Tim Lloyd

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7 Comments

Henk Holterman Over a year ago

char is a type, you need @char. Better use another name. And who wants to know/remember that 48 == '0' ? Think of the poor reader.

Tim Lloyd Over a year ago

@Henk Interesting point re. 48. It looks more obvious to me that normalization is going on.

Henk Holterman Over a year ago

ch - '0' tells a logical story, it is self-documenting. ch - 48 requires knowledge of ASCII codes. .

Tim Lloyd Over a year ago

@Henk We are converting from ASCII, therefore, a knowledge of ASCII or a hint that is what's going on is useful. Replacing it with a meaningful constant would be helpful (e.g. AsciiAdjust), but we're allowed brevity fro code samples.

Henk Holterman Over a year ago

No, we are converting from some (preferably unknown) char encoding.

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Henk Holterman · Accepted Answer · 2011-07-29 09:33:46Z

1

Yes, use a loop. You want a particualr conversion which is not standard:

string numString = "012";

var byteDigits = new byte[numString.Length];
for(int i = 0; i < byteDigits.Length; i++)
    byteDigits[i] = (byte)(numString[i] - '0')

answered Jul 29, 2011 at 9:33

Henk Holterman

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Comments

Stephan Bauer · Accepted Answer · 2011-07-29 09:44:48Z

1

string numString = "012";
var numChars = numString.ToCharArray();
var result = new byte[numChars.Length];

for (int i = 0; i < numChars.Length; i++)
{
   result[i] = System.Convert.ToByte(numChars[i]);
}

edited Jul 29, 2011 at 9:44

answered Jul 29, 2011 at 9:29

Stephan Bauer

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Comments

Henk Holterman · Accepted Answer · 2011-07-29 09:46:10Z

1

string s = "012";
byte[] bytes = s.Select(c => byte.Parse(c.ToString())).ToArray();

edited Jul 29, 2011 at 9:46

Henk Holterman

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answered Jul 29, 2011 at 9:37

Thomas Levesque

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1 Comment

Henk Holterman Over a year ago

I don't get the -1, it's a working solution. Just needed a ')'.

Bob Vale · Accepted Answer · 2011-07-29 09:46:03Z

0

using System.Linq you can do this. This will also skip over non digits.

var sourceString="012";
var result = sourceString.Where(c=>c>='0' && c<='9').Select(c=>(byte)(c-'0')).ToArray();

or if you want invalid characters to just be 255 you could do

var result = sourceString.Select(c=> (c>='0' && c<='9') ? (byte)(c-'0') : 255).ToArray();

answered Jul 29, 2011 at 9:46

Bob Vale

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Comments

V4Vendetta · Accepted Answer · 2011-07-29 09:49:20Z

0

I am not sure if i understand as what you want to achieve, Is this

List<byte> lstint = byval.Select(c => Convert.ToByte(c.ToString())).ToList();

For a Byte array

byte[] bytarr = byval.Select(c => Convert.ToByte(c.ToString())).ToArray();

edited Jul 29, 2011 at 9:49

answered Jul 29, 2011 at 9:39

V4Vendetta

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3 Comments

Tim Lloyd Over a year ago

Strings already present a char enumerator, no need for ToCharArray. OP was also after a byte[].

Henk Holterman Over a year ago

A List<byte> is not a byte[]

V4Vendetta Over a year ago

@Henk Ok .. changed for the byte[] version, thank chibacity .. i missed that part

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