Checking If All The Items In List Occur In Another List Using Linq

I am stuck with a problem here. I am trying to compare items in a list to another list with much more items using linq. For example: list 1: 10,15,20 list 2: 10,13,14,15,20,30,45,5

Solution 1:

How about:

if (!list1.Except(list2).Any())

That's about the simplest approach I can think of. You could explicitly create sets etc if you want:

HashSet<int> set2 = newHashSet<int>(list2);
if (!list1.Any(x => set2.Contains(x)))

but I'd expect that to pretty much be the implementation of Except anyway.

Solution 2:

This should be what you want:

!list1.Except(list2).Any() 

Solution 3:

var result = list1.All(i => list2.Any(i2 => i2 == i));