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ArrayFilter – Filtering arrays of any type, with many options

ArrayFilter – Filtering arrays of any type, with many options

' Filter the input array. It can work with string arrays or arrays of other ' type!' The input array is modified by removing the elements that do not match the ' filter options, but the array is not actually re-sized. The filter results ' will be moved at the beginning of the array, and empty elements will be left ' at the end. The function returns the number of elements that match the filter ' options however, so that you can manually redim the array if you want to.' ' Example:'   Dim arr() As String = {"this is a String", "this is another one",'  "test string", "will it work?", "ok"}'   ' include all the elements that have "string" within them'   Dim numElements As Integer = ArrayFilter(arr, "string", False, False, True)''   Dim i As Integer'   Debug.WriteLine("--- Start ---")'   For i = 0 To numElements - 1'       Debug.WriteLine(arr(i))'   Next'   Debug.WriteLine("--- End ---")''   ' exclude all the 4 elements'   Dim arr2() As Integer = {1, 4, 7, 9, 11, 43, 56, 4, 11, 1}'   numElements = ArrayFilter(arr2, 4, False, False, False)''   Debug.WriteLine("--- Start ---")'   For i = 0 To numElements - 1'       Debug.WriteLine(arr2(i))'   Next'   Debug.WriteLine("--- End ---")Function ArrayFilter(ByVal arr As Array, ByVal search As Object) As Integer    Return ArrayFilter(arr, search, True)End Function' This overloaded version adds the possibility to choose whether the search is ' case sensitive or notFunction ArrayFilter(ByVal arr As Array, ByVal search As Object, _    ByVal caseSensitive As Boolean) As Integer    Return ArrayFilter(arr, search, caseSensitive, True)End Function' This overloaded version adds the possibility to choose whether partial search ' results are accepted or notFunction ArrayFilter(ByVal arr As Array, ByVal search As Object, _    ByVal caseSensitive As Boolean, ByVal exactMatch As Boolean) As Integer    Return ArrayFilter(arr, search, caseSensitive, exactMatch, True)End Function' This overloaded version adds the possibility to choose whether the search ' results are included or excluded in/from the filtered arrayFunction ArrayFilter(ByVal arr As Array, ByVal search As Object, _    ByVal caseSensitive As Boolean, ByVal exactMatch As Boolean, _    ByVal include As Boolean) As Integer    Return ArrayFilter(arr, search, caseSensitive, exactMatch, include, _        arr.GetLowerBound(0), arr.GetUpperBound(0))End Function' This overloaded version adds the possibility to choose the portion of the ' array to be filteredFunction ArrayFilter(ByVal arr As Array, ByVal search As Object, _    ByVal caseSensitive As Boolean, ByVal exactMatch As Boolean, _    ByVal include As Boolean, ByVal first As Integer, ByVal last As Integer) As Integer    Dim strSearch As String    Dim removeElement As Boolean    Dim isStringArr As Boolean    Dim numRemoved As Integer    ' if this is a String array,    If TypeOf arr Is String() Then        isStringArr = True        ' convert the search object to a string, and if the caseSensitive         ' option is not True, convert it to lower case        strSearch = search.ToString()        If Not caseSensitive Then strSearch = strSearch.ToLower()    End If    Dim i As Integer    For i = last To first Step -1        removeElement = False        ' if this is a string array...        If isStringArr Then            ' ...convert the array's item to string, and to lower case is the             ' filter is not case sensitive            Dim strValue As String = CType(arr.GetValue(i), String)            If Not caseSensitive Then strValue = strValue.ToLower()            If exactMatch Then                ' if this is an exact match, remove or leave the element                 ' according to the include option                If strSearch = strValue Then                    If Not include Then removeElement = True                Else                    If include Then removeElement = True                End If            Else                ' if this is a partial match, remove or leave the element                 ' according to the include option                If strValue.IndexOf(strSearch) > -1 Then                    If Not include Then removeElement = True                Else                    If include Then removeElement = True                End If            End If        Else            ' if not a string array, use the Object's Equals method for value             ' comparison            Dim oValue = arr.GetValue(i)            If oValue.Equals(search) Then                If Not include Then removeElement = True            Else                If include Then removeElement = True            End If        End If        If removeElement Then            ' shift elements from arr(index+1) to arr(index)            Array.Copy(arr, i + 1, arr, i, arr.GetUpperBound(0) - i)            ' clear the last element            arr.Clear(arr, arr.GetUpperBound(0), 1)            ' increment the counter of removed elements            numRemoved += 1        End If    Next    Return arr.Length - numRemovedEnd Function

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