// Return a new array with the strings filtered out

Your function isn't returning anything.

loved this kata

Thanks a lot, it's a pity that the latest version available here is 8.0... I wouldn't have thought about this...

Because 'not pattern' matching was introduced in 9.0? https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-9#pattern-matching-enhancements

good kata

def filter_list(l):
    return list(filter(lambda x: isinstance(x, int), l))

im using c#. why i am getting this error for random assertions.

Test Failed
  User mutated the input list!
  Expected and actual are both <System.Collections.Generic.List`1[System.Int32]> with 88 elements
  Values differ at index [0]
  Expected: -8
  But was:  -100

here was my code

using System.Collections.Generic;

public class Kata
{
  public static List<int> ReverseList(List<int> list)
  {
    list.Reverse();
    return list;
  }
}

The function doesn't need to print the list but to return it :-)

It's never a good idea mutating the array/list you're iterating through. You're skipping values like that.

Couldn't agree more.