AttributeError: ntpath.py 和 Tkinter.py 的 __len__ 错误

Question

我在运行一个脚本时遇到了以下错误，脚本在更改目录时出问题了——我该如何修复这个错误呢？

错误追踪信息（最近的调用在最前面）： 文件 "L:\Data_Admin\QA\Metadata_python_toolset\test2\update_Metadata1e.py", 第17行，在 currentPath=os.path.join(root,directory) 文件 "C:\Python26\ArcGIS10.0\lib\ntpath.py", 第96行，在 join assert len(path) > 0 文件 "C:\Python26\ArcGIS10.0\lib\lib-tk\Tkinter.py", 第1722行，在 getattr return getattr(self.tk, attr) 属性错误： len

完整代码

import os, xml, arcpy, shutil, datetime, Tkinter,tkFileDialog
from xml.etree import ElementTree as et 

path=os.getcwd()
RootDirectory=path
arcpy.env.workspace = path
Count=0

Generated_XMLs=RootDirectory+'\GeneratedXML_LOG.txt'
f = open(Generated_XMLs, 'a')
f.write("Log of Metadata Creation Process - Update: "+str(datetime.datetime.now())+"\n")
f.close()

for root, dirs, files in os.walk(RootDirectory, topdown=False):
    #print root, dirs
    for directory in dirs:
        currentPath=os.path.join(root,directory)
        os.chdir(currentPath)
        arcpy.env.workspace = currentPath
        print currentPath
#def Create_xml(currentPath):

        FileList = arcpy.ListFeatureClasses()
        zone="_Zone"

        for File in FileList:
            Count+=1
            FileDesc_obj = arcpy.Describe(File)
            FileNm=FileDesc_obj.file
            check_meta=os.listdir(currentPath)
            existingXML=FileNm[:FileNm.find('.')]
            existingExtension=FileNm[FileNm.find('.'):]
            print "XML: "+existingXML
            #print check_meta
            #if  existingXML+'.xml' in check_meta:
            #newMetaFile='new'
            for f in check_meta:
                if f.startswith(existingXML) and f.endswith('.xml'):
                    print "exists, file name:", f
                    newMetaFile=FileNm+"_2012Metadata.xml"
                    shutil.copy2(f, newMetaFile)
                    break
                else:
                    #print "Does not exist"
                    newMetaFile=FileNm+"_BaseMetadata.xml"

            print "New meta file: "+newMetaFile+ " for: "+File
            if newMetaFile.endswith('_BaseMetadata.xml'):        
                print "calling tkinter"
                root = Tkinter.Tk()
                file = tkFileDialog.askopenfile(parent=root,mode='rb',title='Choose a xml base file to match with: '+File)
                if file != None:
                    metafile=os.path.abspath(file.name)
                    file.close()
                    #print metafile
                    shutil.copy2(metafile,newMetaFile)
                    print "copied"+metafile
                    root.destroy

                else:
                    shutil.copy2('L:\Data_Admin\QA\Metadata_python_toolset\Master_Metadata.xml', newMetaFile)


            print "Parsing meta file: "+newMetaFile
            tree=et.parse(newMetaFile)        
            print "Processing: "+str(File)

            for node in tree.findall('.//title'):
                node.text = str(FileNm)
            for node in tree.findall('.//northbc'):
                node.text = str(FileDesc_obj.extent.YMax)
            for node in tree.findall('.//southbc'):
                node.text = str(FileDesc_obj.extent.YMin)
            for node in tree.findall('.//westbc'):
                node.text = str(FileDesc_obj.extent.XMin)
            for node in tree.findall('.//eastbc'):
                node.text = str(FileDesc_obj.extent.XMax)        
            for node in tree.findall('.//native/nondig/formname'):
                node.text = str(os.getcwd()+"\\"+File)
            for node in tree.findall('.//native/digform/formname'):
                node.text = str(FileDesc_obj.featureType)
            for node in tree.findall('.//avlform/nondig/formname'):
                node.text = str(FileDesc_obj.extension)
            for node in tree.findall('.//avlform/digform/formname'):
                node.text = str(float(os.path.getsize(File))/int(1024))+" KB"
            for node in tree.findall('.//theme'):
                node.text = str(FileDesc_obj.spatialReference.name +" ; EPSG: "+str(FileDesc_obj.spatialReference.factoryCode))
            print node.text
            projection_info=[]
            Zone=FileDesc_obj.spatialReference.name

            if "GCS" in str(FileDesc_obj.spatialReference.name):
                projection_info=[FileDesc_obj.spatialReference.GCSName, FileDesc_obj.spatialReference.angularUnitName, FileDesc_obj.spatialReference.datumName, FileDesc_obj.spatialReference.spheroidName]
                print "Geographic Coordinate system"
            else:
                projection_info=[FileDesc_obj.spatialReference.datumName, FileDesc_obj.spatialReference.spheroidName, FileDesc_obj.spatialReference.angularUnitName, Zone[Zone.rfind(zone)-3:]]
                print "Projected Coordinate system"
            x=0
            for node in tree.findall('.//spdom'):
                for node2 in node.findall('.//keyword'):
                    print node2.text
                    node2.text = str(projection_info[x])
                    print node2.text
                    x=x+1


            tree.write(newMetaFile)

            f = open(Generated_XMLs, 'a')
            f.write(str(Count)+": "+File+"; "+newMetaFile+"; "+currentPath+"\n")
            f.close()

        print "change dir 1"
    print "change dir 2"


    #        Create_xml(currentPath)

Answer 1

可能是你的 os.chdir 让 os.walk 感到困惑。试着在下一次循环之前恢复工作目录。

更好的办法是，如果你为改变目录定义一个上下文管理器，可以使用 with 语句。这里有一个例子，它定义了一个可以这样使用的 chdir 版本：

  for root, dirs, files in os.walk(RootDirectory, topdown=False):
    for directory in dirs:
      currentPath=os.path.join(root,directory)
      with chdir(currentPath):
        # now inside the specified directory
        # after exiting 'with', original directory will be restored