c# - Find indices of particular items in the list using linq

Question

I have a list of integers from 1 to 20. I want the indices of items which are greater than 10 using linq. Is it possible to do with linq?

Thanks in advance

Answer 1

Use the overload of Select which includes the index:

var highIndexes = list.Select((value, index) => new { value, index })
                      .Where(z => z.value > 10)
                      .Select(z => z.index);

The steps in turn:

• Project the sequence of values into a sequence of value/index pairs
• Filter to only include pairs where the value is greater than 10
• Project the result to a sequence of indexes