Vb.net how to filter out the same elements in the array?

Dim filtered = array.GroupBy(
    Function(x) x.Split("#")(0)
) _
.Select(
    Function(x)
        Return x.OrderByDescending(Function(y) Int32.Parse(y.Split("#")(1))) _
        .First()
    End Function
).ToArray()

1. GroupBy does what its name tells you: it 'groups' the elements by a certain condition that we pass - here, we group them by x.Split("#")(0), which means, the first element of the array we get by splitting the string by # (everything before the first # char). The result of this GroupBy call would look like this:
   

   Group 0:
   "100#200#0"
   "100#560#0"
   "100#-320#0"
   "100#-290#0"
   
   Group 1:
   "200#120#0"
   "200#780#0"
   
   Group 2:
   "300#980#0"
   
   Group 3:
   "400#220#0"
   
   Group 4:
   "500#400#0"
   
   Group 5:
   "600#450#0"

   
   
2. For each group, we are interested in the string with the highest "middle value". That's what our select statement does: for each group (of the IGrouping type[^]), which we call x, we return one string. x.OrderByDescending lets us order the elements in the grouping, and its argument lets us decide how to order. We want to order by the "middle value" of the string converted to an integer - that's what Function(y) Int32.Parse(y.Split("#")(1)) does. But we don't want to select the whole sorted collection, we only want the first element: .First().
   
   The result of this Select function is:
   

   "100#560#0"
   "200#780#0"
   "300#980#0"
   "400#220#0"
   "500#400#0"
   "600#450#0"

   
   
3. The return type of Select is an IEnumerable (here an IEnumerable (Of String) because it holds string values), but if you want to have an array, you have to call ToArray on it.