如何在 C# 中重复列表 m 次中的 n 个值？

Question

For example, I have a list

var list = new List<int> { 1, 2, 3 };

and I want to repeat its content 3 times to get in result

{ 1, 2, 3, 1, 2, 3, 1, 2, 3 }

Is there a simpler solution than just AddRange m times in for loop?

Answer 1

using Enumerable.Repeat

var repeatCount = 3; //change this value to repeat n times
var list = new List<int> { 1, 2, 3 };
var result = Enumerable.Repeat(list, repeatCount).SelectMany(x => x).ToList();

Answer 2

You can use LINQ's Enumerable.Range with SelectMany :

list = Enumerable.Range(0, 3)
   .SelectMany(_ => list)
   .ToList();

This will differ from adding to the list though - new list will be created here.