AttributeError: 'unicode' object has no attribute '_arc_object' from arcpy.mapping.ListLayers?

Question

I'm trying to write a script that allows me to list .mxd files in a folder and then list the layers in each map document, however, I keep getting this error:

Traceback (most recent call last): File "C:\Python27\ArcGIS10.1\Lib\site-packages\pythonwin\pywin\framework\scriptutils.py", line 326, in RunScript exec codeObject in main.dict File "C:\Users\Daimon Nurse\Desktop\DFMPROJECT\Scripts\editmapdocument8.py", line 9, in lyr = arcpy.mapping.ListLayers(file) File "C:\Program Files (x86)\ArcGIS\Desktop10.1\arcpy\arcpy\utils.py", line 181, in fn_ return fn(*args, **kw) File "C:\Program Files (x86)\ArcGIS\Desktop10.1\arcpy\arcpy\mapping.py", line 1499, in ListLayers result = mixins.MapDocumentMixin(map_document_or_layer).listLayers(wildcard, data_frame) File "C:\Program Files (x86)\ArcGIS\Desktop10.1\arcpy\arcpy\arcobjects\mixins.py", line 822, in listLayers layers = self.layers File "C:\Program Files (x86)\ArcGIS\Desktop10.1\arcpy\arcpy\arcobjects\mixins.py", line 682, in layers for frame in reversed(self.dataFrames): File "C:\Program Files (x86)\ArcGIS\Desktop10.1\arcpy\arcpy\arcobjects\mixins.py", line 694, in dataFrames return map(convertArcObjectToPythonObject, self.pageLayout.dataFrames) File "C:\Program Files (x86)\ArcGIS\Desktop10.1\arcpy\arcpy\arcobjects\mixins.py", line 678, in pageLayout return convertArcObjectToPythonObject(self._mxd._arc_object.pageLayout) AttributeError: 'unicode' object has no attribute '_arc_object'

This is the code I am using :

import arcpy
import os

PATH2 = r"C:\Users\Daimon Nurse\Desktop\DFMPROJECT"
arcpy.env.workspace = PATH2
arcpy.env.overwriteOutput=True

for file in arcpy.ListFiles("*.mxd"):
    lyr = arcpy.mapping.ListLayers(file)
    print file    

Answer 1

Try converting "file" to a full pathname, then opening the doc with mapping.MapDocument, like this:

for file in arcpy.ListFiles("*.mxd"):
    filePath = os.path.join(PATH2,file)
    print filePath
    MapDoc = arcpy.mapping.MapDocument(filePath)
    lyrList = arcpy.mapping.ListLayers(MapDoc)
    for Lyr in lyrList:
        print Lyr

Answer 2

You are trying to list layers from a string called file that happens to be a map (*.mxd) name.

You need to use arcpy.MapDocument() to make a map document object from that first.

Answer 3

For arcpy.mapping.ListLayers to work, its input must be a map object. Map objects are created with arcpy.MapDocument()

Try:

for file in arcpy.ListFiles("*.mxd"):
    mxd = arcpy.MapDocument(file) 
    lyr = arcpy.mapping.ListLayers(mxd)
    print file