C# LINQ - Loop through list-CodePudding

I have a test LINQ list below

List<test> test=new List<test>();
test.Add(new test("Bakery","[email protected]","Donut"));
test.Add(new test("Bakery","[email protected]","Bagel"));
test.Add(new test("Bakery","[email protected]","Cake"));
test.Add(new test("Produce","[email protected]","Apple"));
test.Add(new test("Dairy","[email protected]","Milk"));
test.Add(new test("Dairy","[email protected]","Yogurt"));

Some departments have more than 1 item. How can loop through the list and send 1 email to each department/email address with the item(s). Send 1 email to [email protected] with Donut, Bagel, Cake in the body. Send 1 email to [email protected] with Apple in the body. Send 1 email to [email protected] with Milk, Yogurt in the body

I don't need help with the email part, just need help to loop through the list and get items per department. Thank you very much!!!

CodePudding user response：

I think, you may use the grouping for the task.

var groups = test.GroupBy(x => x.Email);
foreach (var group in groups)
{
  var email = group.Key; // Exactly the property from GroupBy
  var goods = group.Select(x => x.Good); // Donut, Bagel, Cake...
  var body = string.Join(", ", goods);

  // Now you can send the email with body containing "Donut, Bagel. Cake"
}

Each instance of the group variable contains Key property and the collection of grouped items from the test collection.

Thus, you can use the group either with methods like Select, or with the foreach operator.

CodePudding user response：

List<test> test=new List<test>();
test.Add(new test("Bakery","[email protected]","Donut"));
test.Add(new test("Bakery","[email protected]","Bagel"));
test.Add(new test("Bakery","[email protected]","Cake"));
test.Add(new test("Produce","[email protected]","Apple"));
test.Add(new test("Dairy","[email protected]","Milk"));
test.Add(new test("Dairy","[email protected]","Yogurt"));

foreach (var group in test.GroupBy(x=> x.Department))
{
    var department = group.Key;
    var email = group.First().Email;
    var body = string.Join(", ", group.Select(x => x.Product));

    SendMail(email, department, body);
}