Question

With the following object hierarchy, I need to confirm whether or not all string Id values are present in Inventories of each SearchResult e.g.

Given a string[] list = { "123", "234", "345" } confirm all list values are present at least once in the array of Inventory elements. I’m curious if I can clean this up using one LINQ statement.

SearchResult
--
Inventory[] Inventories

Inventory
--
String Id

Right now, I’m splitting list e.g.

list.Split(').ToDictionary(i => i.ToString(), i => false)

And iterating the dictionary, testing each Inventory. Then, I create a new List<SearchResult> and add items if there are no false values left in the dictionary. This feels clunky.

Code

// instock: IEnumerable<SearchResult>
foreach (var result in instock)
{
    Dictionary<string, bool> ids = list.Split(',').ToDictionary(i => i.ToString(), i => false);
    foreach (var id in ids)
        if (result.Inventory.Any(i => i.Id == id.Key))
            ids[id.Key] = true;

    if (!ids.Any(i => i.Value == false))
        // instockFiltered: List<SearchResult>
        instockFiltered.Add(result);
}

Answer 1

Here is a bit of code I wrote. The advantage here is that it uses a hash map, so it has theoretically linear complexity.

    public static bool ContainsAll<T>(this IEnumerable<T> superset, IEnumerable<T> subset, IEqualityComparer<T> comparer)
    {
        var set = new HashSet<T>(superset, comparer);
        return set.IsSupersetOf(subset);
    }