Question

I want to remove multiple indexes from a linq list, I am using the following code:

slidePart
         .Slide
         .Descendants<DocumentFormat.OpenXml.Presentation.Picture>()
         .ToList()
         .ForEach(pic => pic.Remove());

There are 3 elements in the List and now what I want is to select only the 1st and 3rd element then execute ForEach to remove them.

[Edit]

The Problem is also that Indexes are dynamic.

Answer 1

    var toRemove = new int[] { 1,2,.... };

    slidePart.Slide
        .Descendants<DocumentFormat.OpenXml.Presentation.Picture>()
        .Where((x, i) => toRemove.Contains(i) )
        .ToList()
        .ForEach(pic => pic.Remove());

If your list (toRemove) is large, you may reduce the search time (of Contains) from O(n) to O(1) by changing the declaration of toRemove a little bit

var toRemove = new HashSet<int>(new int[] { 1 });