I have the following method:
namespace ListHelper
{
public class ListHelper<T>
{
public static bool ContainsAllItems(List<T> a, List<T> b)
{
return b.TrueForAll(delegate(T t)
{
return a.Contains(t);
});
}
}
}
The purpose of which is to determine if a List contains all the elements of another list. It would appear to me that something like this would be built into .NET already, is that the case and am I duplicating functionality?
Edit: My apologies for not stating up front that I'm using this code on Mono version 2.4.2.
If you're using .NET 3.5, it's easy:
public class ListHelper<T>
{
public static bool ContainsAllItems(List<T> a, List<T> b)
{
return !b.Except(a).Any();
}
}
This checks whether there are any elements in b
which aren't in a
- and then inverts the result.
Note that it would be slightly more conventional to make the method generic rather than the class, and there's no reason to require List<T>
instead of IEnumerable<T>
- so this would probably be preferred:
public static class LinqExtras // Or whatever
{
public static bool ContainsAllItems<T>(this IEnumerable<T> a, IEnumerable<T> b)
{
return !b.Except(a).Any();
}
}