如何在Linq中按分隔符拆分字符串和多个group by并对它们进行计数？

string str = "apple,banana,orange";
string[] fruits = str.Split(',');

// fruits数组将包含 ["apple", "banana", "orange"]

string str = "apple,banana,orange";
var result = str.Split(',')
                .SelectMany(s => s.Split(','));

// result将包含 ["apple", "banana", "orange"]

List<string> fruits = new List<string> { "apple", "banana", "orange", "apple", "banana" };
var result = fruits.GroupBy(f => f)
                   .Select(g => new { Fruit = g.Key, Count = g.Count() });

// result将包含 [{ Fruit = "apple", Count = 2 }, { Fruit = "banana", Count = 2 }, { Fruit = "orange", Count = 1 }]

string str = "apple,banana,orange,apple,banana";
var result = str.Split(',')
                .SelectMany(s => s.Split(','))
                .GroupBy(f => f)
                .Select(g => new { Fruit = g.Key, Count = g.Count() });

// result将包含 [{ Fruit = "apple", Count = 2 }, { Fruit = "banana", Count = 2 }, { Fruit = "orange", Count = 1 }]