如何在linq C＃中计算字符串的字符串数组中的第一个字母

Question

var query = from str in strdizi
                    where str.StartsWith(str.Substring(0, 1))
                    orderby str
                    group str by str.Substring(str.LastIndexOf(Convert.ToChar(str.Substring(0, 1))))
                        into ws
                        where ws.Count() >= 1
                        select ws;
        foreach (var item in query)
        {
            Console.WriteLine(item.Key + " " + item.Count());
            foreach (var items in item)
            {
                Console.WriteLine(items);
            }
        }

but the output is;

Andy 1

Andy

Arthur 1

Arthur

I want ;

A - 1

Andy

Arthur

Ashlynn

Thanks for helping. Sory for my bad english.

Answer 1

You don't need the where condition, it is enough to group the data by substring:

var strdizi = new string [] {"Andy", "Arthur", "Ashlynn", "Ben", "Chris"};
var query = from str in strdizi
            group str by str.Substring(0, 1 )
            into ws
            where ws.Count() >= 1
            select ws;

foreach (var item in query)
{
    Console.WriteLine(item.Key + " " + item.Count());
    foreach (var items in item)
    {
        Console.WriteLine(items);
    }
}

This gives the results:

A 3
Andy
Arthur
Ashlynn
B 1
Ben
C 1
Chris

Answer 2

As I prefer the method syntax over query syntax, this is how you would do it:

var strdizi = new string [] {"Andy", "Arthur", "Ashlynn", "Ben", "Chris"};
var query = strdizi.GroupBy(g=>g.Substring(0,1));
foreach (var item in query)
{
    Console.WriteLine(item.Key + " " + item.Count());
    foreach (var items in item)
    {
        Console.WriteLine(items);
    }
}