Collection

[Norkis]

Hey,

I used collection, to make object list.

dim v as new collection

I add items using key.

v.add(object, key)

Key is unique integer.

After I add (or replace) item, I need to remove all other items, which key is bigger.

How to do this?

Maybe I should use other class (not collection)?

[plenderj]

''declare the collection
        ''
        Dim myColl As New Collection()
 
        ''add items to it
        ''
        Dim i As Integer
        For i = 0 To 99
            myColl.Add(i, i)
        Next
 
        ''now remove any items where key > intSomeNumber
        ''
        Dim intSomeNumber As Integer = 67
        Dim myItem As New Object(), blnClear As Boolean = False
        Do Until blnClear
            blnClear = True
            For Each myItem In myColl
                If myItem > intSomeNumber Then
                    myColl.Remove("" & myItem)
                    Debug.WriteLine("Remove : " & myItem)
                    blnClear = False
                End If
            Next
        Loop

[mendhak]

What is it about the blnClear boolean that makes it necessary in this loop?

Does it have something to do with the size of the collection decreasing after each Remove method?

[plenderj]

Originally posted by mendhak
What is it about the blnClear boolean that makes it necessary in this loop?

Does it have something to do with the size of the collection decreasing after each Remove method?

Yeah it appears to cache the size of the collection at the start of the loop - so that after a few iterations it's already past the end of the collection...

[mendhak]

Which is why that loop must run several times.

Ok, Thanks.

[Norkis]

Maybe this code would run faster?

Dim vv As New ArrayList
 
Dim i As Integer
       
   For i = 0 To 99
 
         vv.Add(i, i)
 
   Next
 
 
'now remove any items where index > removeFrom
        
Dim removeFrom As Integer = 67
 
vv.RemoveRange(removeFrom, vv.Count-removeFrom)