Split a byte array into different byte arrays

Question

I have a byte array which contains almost 10Kb data. I have to take the data from the same array in multiple of 230 bytes at a time. I tried different methods but not able to achieve the target. Can someone please help me out in this?

I have tried with below code but not serving my purpose.

public static string splitArray(byte[] array, int size)
{

    byte[] myBytes = array; // original byte array
    string[] dataArray = new string[230];

    string dataArray = null;
    for (var i = 0; i < (float)myBytes.Length / size; i++)
    {
        dataArray = myBytes.Skip(i * size).Take(size).ToString();
        Logger.Info($"Length:{dataArray.Length}");
    }

    return dataArray;
}

What methods have you tried? If you're using C# 7.2 or newer, could you use Span<byte>? — ProgrammingLlama
– ProgrammingLlama, Commented Apr 5, 2021 at 9:31
public static string splitArray(byte[] array, int size) { byte[] myBytes = array; // original byte array string[] dataArray = new string[230]; string dataArray = null; for (var i = 0; i < (float)myBytes.Length / size; i++) { dataArray = myBytes.Skip(i * size).Take(size).ToString(); Logger.Info($"Length:{dataArray.Length}"); } return dataArray; } — Ambar
– Ambar, Commented Apr 5, 2021 at 9:45
skip and take is not a good idea for this because those are based on an IEnumerable. You need to use Array.Copy: learn.microsoft.com/en-us/dotnet/api/… And specify the start and end index to copy from one array to another — Jonathan Alfaro
– Jonathan Alfaro, Commented Apr 5, 2021 at 13:50

Dmitrii Bychenko · Accepted Answer · 2021-04-05 14:14:07Z

1

It seems, you want something like this:

Code: (let's generalize the promblem)

public static IEnumerable<T[]> SplitArray<T>(IEnumerable<T> source, int size) {
  if (null == source)
    throw new ArgumentNullException(nameof(source));
  if (size <= 0)
    throw new ArgumentOutOfRangeException(nameof(size));

  List<T> list = new List<T>(size);

  foreach (T item in source) {
    list.Add(item);

    if (list.Count >= size) {
      yield return list.ToArray();

      list.Clear();
    }
  }

  // Do we have last incomplete chunk?
  if (list.Count > 0)
    yield return list.ToArray();
}

Demo:

byte[] data = new byte[] { 10, 20, 30, 40, 50, 60, 70 };

string report = string.Join(Environment.NewLine, SplitArray(data, 3)
  .Select(line => "{" + string.Join(", ", line) + "}"));

Console.Write(report);

Outcome:

{10, 20, 30}
{40, 50, 60}
{70}

Note, that the last chunk can be shorter then required length (3)

Edit: If you want to append 0 to each array, you can do it in the splitting method:

public static IEnumerable<T[]> MySplitArray<T>(IEnumerable<T> source, int size) {
  if (null == source)
    throw new ArgumentNullException(nameof(source));
  if (size <= 0)
    throw new ArgumentOutOfRangeException(nameof(size));

  List<T> list = new List<T>(size + 1);

  foreach (T item in source) {
    list.Add(item);

    if (list.Count >= size) {
      list.Add(default(T));

      yield return list.ToArray();

      list.Clear();
    }
  }

  // Do we have last incomplete chunk?
  if (list.Count > 0) {
    list.Add(default(T));

    yield return list.ToArray();
  }
}

Then you can use the rountine in a loop:

byte[] data = ...

foreach(byte[] chunk in MySplitArray(data, 230)) {
  //TODO: add required code here
  MyFunc(chunk);
}

edited Apr 5, 2021 at 14:14

answered Apr 5, 2021 at 10:49

Dmitrii Bychenko

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5 Comments

Ambar Over a year ago

Thank you Dmitry, i could split the complete array into smaller chunks using your code, but i am not sure how i can use each chunck for further processing. I have to send each of the chunck to other function, also i need to add one more byte (0th byte) into the every chunck before sending it to another function. Can you please help me out?

Jonathan Alfaro Over a year ago

This is not the best way to split an array of bytes of large size. You should use a buffer technique either with a MemorySpan, ArrayCopy, MemoryStream or other similar technique

Dmitrii Bychenko Over a year ago

@Jonathan Alfaro: in case of array of large size I'll try get rid of splitting at all and regesign MyFunc method.

Ambar Over a year ago

Thank you Dmitry! Jonathan, our byte size would go atmost upto 20kb not more than that. Dmitry shall i go with the provided solution then?

Dmitrii Bychenko Over a year ago

@Ambar: why don't you try and see?

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