c# 对list 操作的写法总结

1:统计list 内重复值的数量

List<int> list = new List<int>() { , , , , , , ,  };

var g = list.GroupBy(i => i);

foreach (var item in g)
{
Console.WriteLine("Value:{0} , Count:{1}", item.Key, item.Count());
}

结果:
Value: , Count:
Value: , Count:
Value: , Count:
Value: , Count:

2:统计list内某个值的数量

list.FindAll(delegate(int n) { return n == ; }).Count

List<int> list = new List<int>();
            list.Add(100);
            list.Add(100);
            list.Add(100);
            list.Add(100);
            list.Add(100);
            MessageBox.Show(list.FindAll((ex) => { return ex == 100; }).Count.ToString());