Question

I got a list:
var x = new List<string>(){"a","b","c"}

I am looking for an pretty easy way to change all items after a
example:

var x = new List<string>(){"a","b","c"}
var y = new List<string>(){"d","e","f"}
x.addAfterFirst(y);

result x= "a","d","e","f"

I know that’ x.Skip(1)’ can return me the info. I need to set it.

Answer 1

You can use the Take Extension Method to take the first n items from x and concat them with y using the Concat Extension Method:

List<string> x = new List<string> { "a", "b", "c" };
List<string> y = new List<string> { "d", "e", "f" };

int n = 1;

List<string> result = x.Take(n).Concat(y).ToList();
// result == { "a", "d", "e", "f" }

---

If you want to modify x in-place instead of creating a new list, you can use the RemoveRange Method to remove all items after the first n items, and the AddRange Method to append y to x:

List<string> x = new List<string> { "a", "b", "c" };
List<string> y = new List<string> { "d", "e", "f" };

int n = 1;

x.RemoveRange(n, x.Count - n);
x.AddRange(y);
// x == { "a", "d", "e", "f" }