FindLastIndex

Finds the index of the last occurence of a matched element in the array.

 Public Function FindLastIndex(
	  ByRef Arr As Variant,
	  ByVal AddressOfMatch As Long,
	  Optional ByRef Index As Variant,
	  Optional ByRef Count As Variant ) As Long

Parameters

Arr

[ByRef] Variant. The array to search.

AddressOfMatch

[ByVal] Long. The callback address of the matching criteria method.

Index

[ByRef] Optional. Variant. The starting index in the array to begin the backward search.

Count

[ByRef] Optional. Variant. The number of elements to search.

Return Values

Remarks

The function signature for the callback has a specific format.

 Public Function FindLastIndexCallback(ByRef x As [Array Datatype]) As Boolean
     ' return True if x matches your criteria.
 End Sub
 

The callback method signature needs to have 1 parameter that is of a ByRef definition for the the datatype the same as the array. The callback function must return a Boolean value indicating if the passed-by-ref element matches the criteria of the matching routine.

It is extremely important to define the callback method correctly. If the method is incorrect, the application may crash.

Example

In the examples below, a String array is searched using various criteria. The two callback functions (MatchGreetings, MatchNonGreetings) are defined with 1 parameter of a ByRef String and returns a Boolean. If the array datatype is a Long, the the callback will be defined as a ByRef Long.

None of the values should be changed during the search.

Private Sub Main()
    FindFirstGreeting
    FindLastGreeting
    FindAllGreetings
    FindAllNonGreetings
End Sub

' Searches from the beginning of the arry until the first
' successful match from the MatchGreetings function,
' returning the index the element was found at.
Private Sub FindFirstGreeting()
    Debug.Print cArray.FindIndex(GetStrings, AddressOf MatchGreetings)
End Sub

' Searches from the end of the array until the first
' successful match from the MatchGreetings function,
' returning the index the element was found at.
Private Sub FindLastGreeting()
    Debug.Print cArray.FindLastIndex(GetStrings, AddressOf MatchGreetings)
End Sub

' Finds all of the array elements that pass the criteria of the
' MatchGreetings function. The found elements are placed
' into a new array of the same datatype as the original array
' and returned.
Private Sub FindAllGreetings()
    Dim a() As String
    a = cArray.FindAll(GetStrings, AddressOf MatchGreetings)
    Debug.Print a(0), a(1)
End Sub

' Finds all of the array elements that pass the criteria of the
' MatchNonGreetings function. The found elements are placed
' into a new array of the same datatype as the original array
' and returned.
Private Sub FindAllNonGreetings()
    Dim i As Long
    Dim a() As String
    
    a = cArray.FindAll(GetStrings, AddressOf MatchNonGreetings)
    For i = 0 To UBound(a)
        Debug.Print a(i),
    Next i
End Sub

' Create a sample array of strings to search.
Private Function GetStrings() As String()
    GetStrings = cArray.NewArray(ciString, "One", "Two", "Hello", "Four", "Hi", "Six")
End Function

' Callback method used to match a string element from
' the array to the possible greetings we are searching for.
' The method signature should be a ByRef of the datatype
' of the specific array being searched.
Public Function MatchGreetings(ByRef s As String) As Boolean
    MatchGreetings = ((s = "Hello") Or (s = "Hi"))
End Function

' Callback method used to match a string element from
' the array to determine that we have matched against a non-greeting.
' The method signature should be a ByRef of the datatype
' of the specific array being searched.
Public Function MatchNonGreetings(ByRef s As String) As Boolean
    MatchNonGreetings = Not ((s = "Hello") Or (s = "Hi"))
End Function

' this code produces the following output.
'
' 2
' 4
' Hello         Hi
' One           Two           Four          Six

See Also

Project VBCorLib Overview | Class cArray Overview