ARCGIS中的PYTHON问题

# Import system modules

import sys, string, os   

dir = 'H:\\NDVI\\ndvi'  


 # Import arcpy module

import arcpy

files = os.listdir(dir)

for f in files:

    if os.path.splitext(f)[1] == '.tif':

     # Script arguments...

     Input_raster_file = dir + os.sep + f

     # Local variables...  

    Output_Workspace = "H:\\NDVI\\ndvi\\ASCII"

     # =============== file name process ======================

     basename = os.path.splitext(f)[0];

    Output_raster = Output_Workspace + os.sep + basename + ".txt";

    if os.path.exists(Output_raster) == False:

        print Input_raster_file

        # Process: Raster To Other Format (multiple)...

        arcpy.RasterToASCII_conversion(Input_raster_file,Output_raster)

        print Output_raster