C# Concise way to match a string in a list of strings

Question

In SQL I can write:-

if (product_type in ('abc','def','ghi')) ...

How can I write a similarly concise 'if' statement in C#? I don't want to have to pre-create a named string list variable. Thanks.

Possible duplicate of [Linq select objects in list where exists IN (A,B,C)](http://stackoverflow.com/questions/14257360/linq-select-objects-in-list-where-exists-in-a-b-c) — Arturo Menchaca, May 16 '16 at 16:27
@ArturoMenchaca I don't this it is a direct duplicate because the question is asking how to do it without assigning it to a variable. — Matt Rowland, May 16 '16 at 16:29

score 1 · Answer 1 · answered May 16 '16 at 16:25

1

To simplify this you would use this line.

if (new[] {"abc", "def", "ghi"}.Contains(product_type)) //...

Don't forget to add the declaration

using System.Linq;

answered May 16 '16 at 16:25

Matt Rowland

4,575
4
25
34

score 0 · Accepted Answer · answered May 16 '16 at 16:24

You can create an anonymous collection inline and perform the same method calls on it as if it were named.

var product_type = "abc";
// Array
var result = new [] {"abc", "def", "ghi"}.Contains(product_type); // result == true.
// List
var listResult = new List<string> {"abc", "def", "ghi"}.Contains(product_type);

score 0 · Answer 3 · answered May 16 '16 at 16:30

...or you can create an extension to have the In for everything

public static bool In<T>(this T obj, IEqualityComparer<T> comparer, params T[] list)
        {
            if (comparer == null)
                return list.Contains(obj);
            else
                return list.Contains(obj, comparer);
        }

        public static bool In<T>(this T obj, params T[] list)
        {
            return In(obj, null, list);
        }

so you could write something like:

if ( product_type.In( "abc", "def", "ghi" ) ) ...

score 0 · Answer 4 · answered May 16 '16 at 16:36

0

I figured it out:-

if (new List<string> {"Fred", "Jim", "Harry"}.Contains("Jim"))

answered May 16 '16 at 16:36

andyabel

335
4
15

Thanks Yvette. I posted my answer before I noticed that anyone had replied. – andyabel May 16 '16 at 16:47

C# Concise way to match a string in a list of strings

4 Answers4