Array Concatenation in C#

Question

1- How to smartly initialize an Array with 2 (or more) other arrays in C#?

double[] d1=new double[5];
double[] d2=new double[3];
double[] dTotal=new double[8];// I need this to be {d1 then d2}

2- Another question: How to concatenate C# arrays efficiently?

Thanks

Answer 1

var dTotal = d1.Concat(d2).ToArray();

You could probably make it 'better' by creating dTotal first, and then just copying both inputs with Array.Copy.

Answer 2

You need to call Array.Copy, like this:

double[] d1 = new double[5];
double[] d2 = new double[3];
double[] dTotal = new double[d1.length + d2.length];

Array.Copy(d1, 0, dTotal, 0, d1.Length);
Array.Copy(d2, 0, dTotal, d1.Length, d2.Length);

Answer 3

You could use CopyTo :

double[] d1=new double[5];
double[] d2=new double[3];
double[] dTotal = new double[d1.Length + d2.Length];

d1.CopyTo(dTotal , 0);
d2.CopyTo(dTotal , d1.Length);