Question

I know LINQ but my knowledge is pretty much only selects, where, orderby and all of the most common functions. Now I have a need to do something that I think is really difficult and
maybe not even possible to do just with LINQ. What I have is a list of people. That’s east
to query but I need to create a text string from that list. The text string has to give a letter followed by the name of each person.

IList<person> Person

I need to be able to have a LINQ statement that checks through the Person list. I need
to be able to look for names that appear more than once. So far I have the following. It works okay but doesn’t give everything needed:

Person[0] name="Fred" &
Person[1] name="Pete" &
Person[2] name="Tony" the var abc = "a) Fred. b) Pete. c) Tony 

var a = "";
foreach (var person in _persons
            .Select((data, value) => new { Data = data, Value = value })
        {
            a = a + (char)(details.Value + 64) + details.name
        }

What I need is the additional functionality so that:

Person[0] name="John" then var abc = "a) John."

Person[1] name="John" &
Person[3] name="John" then var abc = "b) & d) John."

Person[1] name="John" &
Person[2] name="John" &
Person[3] name="John" then var abc = "b),c) & d) John."

In other words, get the names and put a character before them that shows what position the name is in the list. However if the name appears twice then instead of a)name1. b)name1 I need to get a),b) name.

It’s something I can’t really figure out how to do. I would appreciate any advice or pointers that anyone can give me.

Answer 1

Given:

var persons=new[] {"Fred", "John", "John", "Pete", "John"};

You can write:

        char id = 'a';
        foreach (var row in persons
            .Select(w => new { id = id++, name = w })
            .GroupBy(w => w.name)
            .Select(w => w
                .Select(ww => ww.id + ")")
                .Aggregate((c, n) => c + "&" + n)
                + " " + w.Key))
        {
            Console.WriteLine(row);
        }

And that gives you:

a) Fred
b)&c)&e) John
d) Pete