SImplifying with LINQ - Basic selection

Question

Hello

foreach (var person in peopleList.Where(person => person.FirstName == "Messi"))
{
        selectPeople.Add(person);
}

I am just wondering if there is any way to simplify this using LINQ.

Like rather than look at all the people I was trying to use LINQ to just fill a list with the "Messi"'s... was trying something like...

var selectPeople = peopleList.Select(x=>x.FirstName=="Messi");

Then I could just add everyone in that list without a check. But it doesn't quite work as planned.

Maybe there's no point simplifying that expression. But the question seemed worthwhile just to strengthen my LINQ knowledge.

Answer 1

You're close. Practically done without knowing it.

var selectPeople = peopleList.Where(x=>x.FirstName == "Messi");

That will create an IEnumerable<X>, where X is whatever type that's in peopleList.

The query expression syntax would be

var selectPeople = from person in peopleList
                   where person.FirstName == "Messi"
                   select person;

And to get it in concrete List format, I believe you've also already discovered the .ToList() extension.

Answer 2

What type is peopleList? I believe it must be a type of IEnumerable for the LINQ to work.

var selectPeople = peopleList.AsEnumerable().Select(x=>x.FirstName=="Messi");

Since it is a List<X> type call AsEnumerable() on the list and tack on your select and it should work.

Answer 3

var selectPeople = new List<Person>(peopleList.Where(x=>x.FirstName=="Messi"));

or if you already have a list:

selectPeople.AddRange(peopleList.Where(x=>x.FirstName=="Messi"));