Q:

Is there an "AllIndexesOf" method?

Background:
I'm working on an evaluator (I know there's solutions available, but I need some features that I need to implement myself). I need to find all occurrences of open brackets in the evaluation. However, for that I need all the indexes of the brackets.
Question:
Is there something like an AllIndexesOf method that returns a int[], or IEnumerable<int>?

A:

There is not but you can get all the indexes using the following LINQ query. 
int number  = 10;
int[] intArray = new[] { 1, 32, 10, 5, 65, 6, 10, 10 };
var allIndexes = intArray.Select((r,i)=> new {value = r, index = i})
                         .Where(r=> r.value == number)
                         .Select(r=> r.index);

allIndexes will contain 2,6 and 7

A:

You also can use Enumerable.Range
 var indexes = Enumerable.Range(0, list.Count)
                         .Where(index => list[index] == yourValue);

