hi i have this kind of array
int[] arrayint = new int[32];
and it contains
arrayint[0] = 99
arrayint[1] = 121
arrayint[2] = 99
arrayint[3] = 66
...
is there a simple way to copy that integer array into a byte array like i want to make this byte array
byte[] streambit;
and it should be the same to the arrayint value
i want to be like this the output
streambit[0] = 99
streambit[1] = 121
streambit[2] = 99
streambit[3] = 66
...
streambit = arrayint.Select(i => (byte)i).ToArray();
Just make sure that you have no value greater than 255.
i => (byte)i is called a lambda expression, a special notation for an anonymous function. In this case, it's a function taking a parameter, converting it to int, then returning it. The Select method takes every element of the collection, then call the lambda on them. The ToArray method copies the result to an array.Without LINQ (useful when targeting .Net 2.0 for instance):
byte[] bytearray = Array.ConvertAll<int, byte>(arrayint, (z) => (byte)z);
Well yeah, much more faster than LINQ:
Test code (could be improved, but this gives an idea):
private static void Main(string[] args)
{
int[] arrayint = new int[40000];
arrayint[0] = 99;
arrayint[1] = 157;
arrayint[2] = 1;
arrayint[3] = 45;
byte[] bytearray;
Stopwatch sw = Stopwatch.StartNew();
for (int i = 0; i < 10000; i++)
{
bytearray = Array.ConvertAll<int, byte>(arrayint, (z) => (byte)z);
}
sw.Stop();
Console.WriteLine("ConvertAll took {0} ms", sw.ElapsedMilliseconds);
sw = Stopwatch.StartNew();
for (int i = 0; i < 10000; i++)
{
bytearray = arrayint.Select(z => (byte)z).ToArray();
}
sw.Stop();
Console.WriteLine("LINQ took {0} ms", sw.ElapsedMilliseconds);
Console.ReadLine();
}
Result:
ConvertAll took 1865 ms
LINQ took 6073 ms
Array.ConvertAll. Seems indeed a better choice. When executing the Linq query, the results are stored in an internal buffer, then copied to an array. Array.ConvertAll directly allocates an array and makes the conversion during the copy. It probably explains the huge performance improvement.streambit=arrayint.Where(x=>x>=0&&x<=255).Select(y=>(byte)y).ToArray();
