C#字符串转数组，数组转字符串，后遍历数组

string ids="5,1,6,3,5,7,8,9,1,5,6,"
var temp = ids.Split(",".ToCharArray(), StringSplitOptions.RemoveEmptyEntries).Select(a=>a.ToInt()).ToArray();
 
==>temp=[5,1,6,3,5,7,8,9,1,5,6]

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  string str = "1,2,3,4,5,6,7";
            string[] strArray = str.Split(','); //字符串转数组
            str = string.Empty;
            str = string.Join(",", strArray);//数组转成字符串

//声明数组. 第一种方法. 声明并分配元素大小.
13             int[] Myint = new int[30];
14             Myint[0] = 30;
15             Myint[1] = 50;
16             // 以此类推, 起始下标为0
17             //-------------------------------
18             // 声明数组,第二种方法, 声明并直接赋值,没有指定元素大小.
19             int[] Myint1 = { 20,10,50,65,18,90}; 
20             //------------------------------------------
21             //声明数组,第三种方法, 声明并分配大小,且赋值.
22             int[] i = new int[5] { 10, 20, 30, 40, 50 };
23 
24             // -----------------------------------------------
25             // foreach循环遍历数组..
26             int[] Sum = new int[50];
27             Random rd = new Random();
28            // 先用for循环给数组取随机数.
29             for (int s = 0; s <= Sum.Length - 1; s++)  // Sum.Length是数组的一个属性,Length代表数组的长度
30             {
31                 Sum[s] = rd.Next(100);
32             }
33            // 遍历数组输出
34             foreach (int t in Sum)
35             {
36                 Console.WriteLine(t);
37             }