C#: Replacing loops with LINQ

What would be the equivalent for these code samples in LINQ (C#):

    int[] items = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

int number = -1;
foreach (int i in items) 
{
    if (i == 5) 
    {
        number = i;
        break;
    }
}

And how would you replace a for loop with two (or more) conditions in LINQ? (it is similar to the code above, couldn't come up with a better example. Imagine that other 开发者_运维百科conditions or checks happen there in the for loop)

    int[] items = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

int number = -1;

for (int i = 0; i < items.Length && number == -1; i++) 
{
    if (items[i] == 5)
        number = items[i];
}

And the third piece of code, how would this be translated in LINQ:

    List<int> items2 = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

int i = items2.Count - 1;

for (; i > 0; i--)
    items2.RemoveAt(i);

Thanks in advance.

The first two are pretty odd, but basically they're effectively:

int number = items.Contains(5) ? 5 : -1;

or

int number = items.Any(x => x == 5) ? 5 : -1;

An alternative way of doing this:

int number = items.Where(x => x == 5).DefaultIfEmpty(-1).First();

If you can come up with more realistic operations, we can come up with more sensible LINQ queries :)

The third snippet can't really be translated into LINQ as it's not a query - it's mutating the list.

As Jon points out, the last one can't be translated to LINQ. However, it can be simplified as:

var survivers = 1;
items2.RemoveRange(survivers , items2.Count - survivers);