How to split a byte array by a particular array value in c#?
byte[] largeBytes = [70,68,49,59,117,49,59,112];
I just want to split the array bye "59" so that I can get 3 byte arrays. I have tried a lot ,couldn't find the solution. thanks in advance
The easiest solution is to use the Split extension method from MoreLINQ :
byte separator=59;
var triplets=largeBytes.Split(separator);
This will return an IEnumerable of IEnumerable<byte>. You can convert it to an IEnumerable<byte[]> with ToArray():
var triplets=largeBytes.Split(separator).Select(triplet=>triplet.ToArray());
Or you can do roughly what the extension method does - create an iterator that checks each input element until it finds the separator and places each character in an array:
public static IEnumerable<List<T>> Split<T>(this IEnumerable<T> source, T separator)
{
List<T> result=new List<T>(3);
foreach(T item in source)
{
if (item == separator)
{
yield return result;
result=new List<T>(3);
}
else
{
result.Add(item);
}
}
yield return result;
}
You can use this extension method in the same way:
byte separator=59;
var triplets=largeBytes.Split(separator);
or
var triplets=MyExtensionsClass.Split(largeBytes,separator);
MoreLINQ's version is a lot more versatile, as it allows you to specify a maximum number of splits, or transform the input into another form
If you want to include the separator, you put result.Add before the first if. A better option would be to add an include parameter:
public static IEnumerable<List<T>> Split<T>(this IEnumerable<T> source, T separator,bool include=false)
{
List<T> result=new List<T>(3);
foreach(T item in source)
{
if (item == separator)
{
if (include) result.Add(item);
yield return result;
result=new List<T>(3);
}
else
{
result.Add(item);
}
}
yield return result;
}
here is the algorithm on how you can achieve this
//Here I'm not including 59 in the sub arrays
var largeBytes = new byte[] {70,68,49,59,117,49,59,112};
var lists = new List<List<byte>>();
const int marker = 59;
var tempLst = new List<byte>();
foreach (var largeByte in largeBytes)
{
if (largeByte==marker)
{
lists.Add(tempLst);
tempLst=new List<byte>();
}
else
{
tempLst.Add(largeByte);
}
}
lists.Add(tempLst);
You can use Array.IndexOf(largeBytes, (byte)59, index) where index will be last found index (0 in beginning) in loop, until function returns -1 (no more 59 found in array).
On boundaries created by (byte)59, copy some sub-array as is written in this answer: Getting a sub-array from an existing array
You could use IEnumerable's GroupBy to perform the split:
byte[] largeBytes = new byte[] {70,68,49,59,117,49,59,112};
byte split = 59;
long index = 0;
var results = largeBytes.GroupBy(b => index += Convert.ToInt64(b==split));
foreach (var result in results) {
Console.WriteLine($"Group Key: {result.Key}");
foreach (var value in result) {
Console.WriteLine($" - Value: {value}");
}
}
Just for fun, here's a way to do it using C#7's Tuples:
byte[] largeBytes = new byte[] {70,68,49,59,117,49,59,112};
byte split = 59;
long index = 0;
var results = largeBytes.Select(x => ((index += Convert.ToInt64(x == 59)),x));
foreach (var tuple in results) {
Console.WriteLine($"{tuple.Item1}: {tuple.Item2}");
}
Demo: http://csharppad.com/gist/079cc46095bb938f716587693d7ea8af
