B4A Class [B4X] List2

Discussion in 'Additional libraries, classes and official updates' started by LucaMs, Aug 8, 2018.

  1. LucaMs

    LucaMs Expert Licensed User

    Description: A simple class to add 3 methods to the native List.

    • IndexOf2(Item As Object, StartIndex As Int) As Int
      • Returns the index of the specified item starting the search from StartIndex. Returns -1 if Item was not found.
    • GetAllIndexes(Item As Object) As List
      • Returns a list of indexes of the specified item. An initialized empty list will be returned if no items will be found.
    • Count(Item As Object) As Int
      • Returns the number of occurrences of Item.

    • List
      • Sets/Gets the list to work with.

    B4A example:
    Sub Process_Globals
    Private lstNames As List
    Private lst2Names As List2
    End Sub

    Sub Activity_Create(FirstTime As Boolean)
    Dim IndexOf As Int
       IndexOf = lst2Names.IndexOf2(
    "Barbara"2' starts from Claudia
       Log("Index: " & IndexOf)
    Dim lstIndexs As List
       lstIndexs = lst2Names.GetAllIndexes(
    For Each Index As Int In lstIndexs
    Log(Index & TAB & lstNames.Get(Index))
    Log("Count: " & lst2Names.Count("Barbara"))
    End Sub

    a) I'm not sure it will work on B4i - I cannot test it
    b) It would be possible to implement a Next method, to search for the next occurrence without having to pass the start index.
    c) You could move the 3 methods to an utility code module, changing them just a little (passing the source list to them).

    Attached Files:

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