Fast and clever way to get the NON FIRST segment of a C# string

Question

I do a split(\' \') over an string and I want to pull the first element of the returned string in order to get the rest of the string.

f.e. \"THIS IS

Answer 1

Do NOT use the Split function - a) it looks for every ' ' symbol there is, not just the first one. b) this approach will involve lots of copying data around in memory which is rather slow operation for strings.

var a = "THIS IS AN AMAZING STRING";
string result;
var index = a.IndexOf(' ');
if (index == -1)
    result = null;
else
    result = a.Substring(index + 1);

Since the title of the question mentions array, not string, it is worth mentioning the ArraySegment class - this enables you to create a pointer to part of the array (without creating a new array and copying data):

var a = new int[] { 0, 1, 2, 3 };
var segment = new ArraySegment(a, 1, a.Length - 1);