Question

Is there some utility to check whether a sequence contains multiple elements instead of using Contains repeatedly?

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

for (int i = 0; i < 10; i++)
{
    containter.Add("string #" + i);
}

if (containter.Contains("string #2") &&       //Is it possible to replace this with one call passing two strings to improve efficiency 
    containter.Contains("string #6"))
{
    //Do Something
}

Answer 1

According to the updated question, I’ve modified my answer:

List<string> containter = new List<string>();
for (int i = 0; i < 10; i++)
{
    containter.Add("string #" + i);
}
//define a checklist
List<string> checkList = new List<string> { "string #2", "string #6" };
//we're in, if every item in checkList is present in container
if (!checkList.Except(containter).Any())
{
    Console.WriteLine("true");
}

Still you may use Any. But in this context it would be nice to use Except method.

If every item in checkList is present in the container the resulting sequence would contain no elements, so Any should return false.