#include  <MsgBoxConstants.au3>

Example()

Func Example()
        ; Declare a map and assign with various keys value pairs.
        Local $mMap[]
        $mMap["Jasper"] = "Jasper value"
        $mMap["Beethoven"] = "Beethoven value"
        $mMap["Pinky"] = "Pinky value"

        ; Read keys
        Local $aKeys = MapKeys($mMap)
        Local $sData = ""
        ; Read values
        For $i = 0 To UBound($aKeys) - 1
                $sData &= $aKeys[$i] & ": " & $mMap[$aKeys[$i]] & @CRLF
        Next
        ; Display result
        MsgBox($MB_SYSTEMMODAL, "", $sData & @CRLF & _
                        'Beethoven exists: ' & MapExists($mMap, "Beethoven") & @CRLF & 'Beethoven equals Null: ' & ($mMap["Beethoven"] == Null))

        ; Clear a key by setting it to Null. The key will still exist in the map.
        $mMap["Beethoven"] = Null

        ; Re-read keys and values
        $aKeys = MapKeys($mMap)
        $sData = ""
        For $i = 0 To UBound($aKeys) - 1
                $sData &= $aKeys[$i] & ": " & $mMap[$aKeys[$i]] & @CRLF
        Next
        ; Display the values of the map keys. Notice how the "Beethoven" key now contains an empty value (Null).
        MsgBox($MB_SYSTEMMODAL, "", $sData & @CRLF & _
                        'Beethoven exists: ' & MapExists($mMap, "Beethoven") & @CRLF & 'Beethoven equals Null: ' & ($mMap["Beethoven"] == Null))

        ; Remove the "Beethoven" key entirely.
        MapRemove($mMap, "Beethoven")

        ; Re-read keys and values
        $aKeys = MapKeys($mMap)
        $sData = ""
        For $i = 0 To UBound($aKeys) - 1
                $sData &= $aKeys[$i] & ": " & $mMap[$aKeys[$i]] & @CRLF
        Next
        ; Display the values of the map keys. Notice how the "Beethoven" key is no longer exists.
        MsgBox($MB_SYSTEMMODAL, "", $sData & @CRLF & _
                        'Beethoven exists: ' & MapExists($mMap, "Beethoven") & @CRLF & 'Beethoven equals Null: ' & ($mMap["Beethoven"] == Null))

EndFunc   ;==>Example