function arr2lon, arr

    num = n_elements(arr)

  ; convert all the arr to long
    type = datatype(arr[0])
    case type of
        'INT': arr_long = long(arr)
        'BYT': arr_long = long(arr)
        'LON': arr_long = arr
        'UIN': arr_long = long(arr)
        'ULO': arr_long = long(arr)
        'L64': arr_long = long(arr)
        'U64': arr_long = long(arr)
        
        'FLO': arr_long = floor(arr)
        'DOU': arr_long = floor(arr)
        'COM': arr_long = floor(float(arr))
        
        'STR': begin
            arr_long = replicate(-1L, num)
            for i=0L,num-1 do begin
                if strnumber(arr[i]) then arr_long[i] = long(arr[i])
            end
        end
        else: begin
            arr_long = replicate(-1L, num)
            if (keyword_set(VERBOSE)) then begin
                print, 'oc_getline_sao: arr must be numbers or strings'
            endif
        endelse
    endcase

    return, arr_long

end