Using Linq to Filter a list

So yesterday I made this post on applying a filter or map on a list.  Now let’s have a look at how we can do this with Linq.

First the list:

List<string> list = new List<string>();

list.Add("Anne");

list.Add("Brian");

list.Add("Pieter");

list.Add("Wayne");

list.Add("Shane");

list.Add("Susan");

list.Add("Xavier");

Plain old Linq:

// Plain old Linq

var linqFiltered = from item in list

                            where item.StartsWith("S")

                            select item;

Using the Where extension method:

// Linq with the Whete extension method only

var linqListFiltered2 = Enumerable.Where(list, i => i.StartsWith("S"));

And for me the most readable:

// Linq using the Where extension method on the list

var linqListWhereFiltered = list.Where(i => i.StartsWith("S"));

You can even create your own Where method:

static IEnumerable<T> Where<T>(IEnumerable<T> sequence, Func<T, bool> predicate)

{

    foreach (var item in sequence)

        if (predicate(item))

            yield return item;

}

And you can use it like this:

var myLinqListFiltered = Where(list, i => i.StartsWith("S"));

I see so many uses and possibilities for the Linq style code as well as extension methods.