[GIS] Arcpy ListLayers function returns only the first sub layer in a group layer (as opposed to the group layer AND all sub layers of that group)

arcgis-10.1arcpy

I thought the arcpy.mapping.ListLayers function in ArcGIS 10.1 was supposed to return group layers AND all of their sub-layers, but my script is only outputting the first sub-layer in a group layer. Can anyone see why by looking at my code? Thanks! (p.s. the purpose of my code is to output a text file – code omitted – that lists all of the layers in a specified directory and the layers' properties).

In ArcGIS 10.1 Desktop Help it says:

Group layers are treated just like layers. The index values are simply generated from top to bottom as they appear in the table of contents or the way they would appear in a layer file.

Code:

layerList = arcpy.ListFiles("*.lyr")
for layer in layerList:
    path = os.path.join(directory, layer)
    lyrFile = arcpy.mapping.Layer(path)

    for lyr in arcpy.mapping.ListLayers(lyrFile):

        try:
            if lyr.supports("DATASETNAME") and lyr.supports("TRANSPARENCY") and lyr.supports("DEFINITIONQUERY") and lyr.supports("SHOWLABELS"):
                doc.write("{0}, {1}, {2}, {3}, {4}, {5}, {6}, {7}"
                          .format(lyr.name, lyr.datasetName, str(lyr.transparency), str(lyr.visible), lyr.definitionQuery, str(lyr.showLabels), str(lyr.minScale), str(lyr.maxScale)))
                doc.write("\n")
                break

            if lyr.supports("DATASETNAME") and lyr.supports("TRANSPARENCY") and lyr.supports("DEFINITIONQUERY") and not lyr.supports("SHOWLABELS"):
                doc.write("{0}, {1}, {2}, {3}, {4}, {5}, {6}, {7}"
                          .format(lyr.name, lyr.datasetName, str(lyr.transparency), str(lyr.visible), lyr.definitionQuery, " ", str(lyr.minScale), str(lyr.maxScale)))
                doc.write("\n")
                break

            if lyr.supports("DATASETNAME") and lyr.supports("TRANSPARENCY") and not lyr.supports("DEFINITIONQUERY") and not lyr.supports("SHOWLABELS"):
                doc.write("{0}, {1}, {2}, {3}, {4}, {5}, {6}, {7}"
                          .format(lyr.name, lyr.datasetName, " ", str(lyr.visible), " ", " ", str(lyr.minScale), str(lyr.maxScale)))
                doc.write("\n")
                break

            if lyr.supports("DATASETNAME") and not lyr.supports("TRANSPARENCY") and not lyr.supports("DEFINITIONQUERY") and not lyr.supports("SHOWLABELS"):
                doc.write("{0}, {1}, {2}, {3}, {4}, {5}, {6}, {7}"
                          .format(lyr.name, lyr.datasetName, " ", " ", str(lyr.visible), " ", " ", str(lyr.minScale), str(lyr.maxScale)))
                doc.write("\n")
                break

            if not lyr.supports("DATASETNAME") and not lyr.supports("TRANSPARENCY") and not lyr.supports("DEFINITIONQUERY") and not lyr.supports("SHOWLABELS"):
                doc.write("{0}, {1}, {2}, {3}, {4}, {5}, {6}, {7}"
                          .format(lyr.name, " ", " ", str(lyr.visible), " ", " ", str(lyr.minScale), str(lyr.maxScale)))
                doc.write("\n")
                break

        except KeyError:
            pass

Best Answer

Your loop is apparently terminating after the first pass. What if you remove the 'break's and replace the 'if's with 'elif's?

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Typo in your code. Should be:

targetGroupLayer = arcpy.mapping.ListLayers(mxd, "Group", df)[0]

otherwise targetGroupLayer is a list.

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For the second problem, I contacted the author (as suggested by DWynne) who gave the correction:

for filename in dirpath[2]:

That corrected the problem. The author told me he contacted Esri shortly after this made it into print but Esri hasn't changed it on the web. He told me he'd contact them again.

For the first problem of this script not listing layers in a group layer, this ought to fix that. Where the code says:

for layer in arcpy.mapping.ListLayers(mxd):

I added after it (sorry, I know the indenting isn't correct)

if lyr.supports("DATASOURCE"):

I found this on an Esri Help page. I'll try it out when I'm back at work. I hope this helps others who have run across this issue.

I have tested this with the problem of the script not listing layers within a group. I also expanded it to allow the output CSV to be automatically named based on the file or folder entered. Here is my code; I hope someone can make use of it.

#Import modules...
import arcpy, os, fnmatch, csv

#User input variables...
mxddirectory = arcpy.GetParameterAsText(0)
mxd_single = arcpy.GetParameterAsText(1)
outputcsvlocation = arcpy.GetParameterAsText(2)

#Create an empty list of ArcMap documents to process...
mxd_list=[]

#If an output location for the CSV is specified, use it...
if len(outputcsvlocation) > 0:
  outputcsvlocation_2 = outputcsvlocation
#...otherwise if a singe MXD is specified, name the CSV for it, or...
elif len(mxd_single) > 0:
  outputcsvlocation_2 = mxd_single.replace(".mxd",".csv")
#...if a folder location is specified, save a CSV called ListLayers.csv in that folder.
else:
  outputcsvlocation_2 = mxddirectory + "\ListLayers.csv"

#If a user defined a single mxd, add its path to the list...
if len(mxd_single) > 0:
  mxd_list.append(mxd_single)
#Otherwise walk through the input directory, adding paths for each .mxd file found to the list...
else:
  for dirpath in os.walk(mxddirectory):
    for filename in dirpath[2]:
      if fnmatch.fnmatch(filename, "*.mxd"):
        mxd_list.append(os.path.join(dirpath[0], filename))

#Iterate the list of mxd paths and gather property values then write to csv file...
if len(mxd_list) > 0:
  #Create the csv file...
  outputcsv = open(outputcsvlocation_2,"wb")
  writer = csv.writer(outputcsv, dialect = 'excel')
  #Write a header row to the csv file...
  writer.writerow(["mxdpath", "layername", "layerdescription", "layersource"])
  #Iterate through the list of ArcMap Documents...
  for mxdpath in mxd_list:
    mxdname = os.path.split(mxdpath)[1]
    try:
      mxd = arcpy.mapping.MapDocument(mxdpath)
      #Iterate through the ArcMap Document layers...
      for layer in arcpy.mapping.ListLayers(mxd):
        if layer.supports("DATASOURCE"): #List all layers that have data, skipping group layers.
          layerattributes = [mxdpath, layer.longName, layer.description, layer.dataSource]
          #Write the attributes to the csv file...
          writer.writerow(layerattributes)
    except:
      arcpy.AddMessage("EXCEPTION: {0}".format(mxdpath))
    del mxd
  #close the csv file to save it...
  outputcsv.close()
#If no ArcMap Documents are in the list, then notify via an error message...
else:
  arcpy.AddError("No ArcMap Documents found. Please check your input variables.")

Thanks to all, especially the original code author.

Best Answer

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