topic Re: arcpy.describe in stand alone script in Python Questions

arcpy.describe in stand alone script

RandyBurton — Sat, 11 Dec 2021 17:36:21 GMT

Does Describe work differently in a stand-alone script vs. a script run inside ArcMap? More specifically, does Describe use the workspace if one is specified? Here's the script:

import arcpy

gdb = r'C:\Path\To\Default.gdb' # path to a file geodatabase
arcpy.env.workspace = gdb

for fc in arcpy.ListFeatureClasses("*"):
        desc = arcpy.Describe(fc)
        print "{} - {}".format(fc, desc.dataType)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Here's the folder structure:

Note that there is a folder outside the file geodatabase with the same name as a feature inside it - in this case "point_fc".

Here are the results:

# Outside ArcMap in stand-alone script:
point_fc - Folder
line_fc - FeatureClass
polygon_fc - FeatureClass

# In ArcMap's Python window:
point_fc - FeatureClass
line_fc - FeatureClass
polygon_fc - FeatureClass‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

The stand-alone script picked up the folder, whereas the script when ran in ArcMap picked up the feature class. Is this expected behavior for Describe?

Re: arcpy.describe in stand alone script

DanPatterson_Retired — Sat, 11 Dec 2021 17:36:24 GMT

In the middle of that link, there is a suggestion that if you aren't sure about a property you should use the 'hasattr' check. I would put both in if you aren't sure. Also, can you rename your folder and featureclass to see if the duplicate naming is doing some 'go that one already' filtering.

I don't think datatype is sufficient in all situations so an extra check especially if duplicate names of objects appear.

Below is a suggestion from the help for checking for other attributes once a datatype is specified

if hasattr(desc, "dataType"):
    print "DataType:    " + desc.dataType
if hasattr(desc, "catalogPath"):
    print "CatalogPath: " + desc.catalogPath
‍‍‍‍

so I would be inclined to check whether if has 'folder' properties as well and featureclass properties too

Re: arcpy.describe in stand alone script

RandyBurton — Sat, 11 Dec 2021 17:36:27 GMT

There are several ways to work around this issue. Renaming the folder is one option. Or this adjustment to the code will also work:

for fc in arcpy.ListFeatureClasses("*"):
        desc = arcpy.Describe(gdb+'\\'+fc) # include gdb/workspace
‍‍

I was expecting Describe to use the declared workspace in a stand-alone script. But, apparently, it starts with the folder that contains the geodatabase. This is an example where scripts work slightly different between ArcMap's Python window and a stand-alone script.

Using hasattr to check for properties is a good suggestion.

Re: arcpy.describe in stand alone script

JoshuaBixby — Sun, 19 Nov 2017 22:37:16 GMT

What version of ArcGIS are you running? I just testing your code running 10.5.1, and I cannot replicate your results. I get the same results running in a standalone script and running in the interactive Python window.

Re: arcpy.describe in stand alone script

RandyBurton — Sun, 19 Nov 2017 22:47:19 GMT

Version is ArcMap 10.5

Re: arcpy.describe in stand alone script

DanPatterson_Retired — Sun, 19 Nov 2017 22:59:07 GMT

Did you create the same structure Joshua with the duplicates?

Randy what was in the folder just in case that has an impact as well?

Re: arcpy.describe in stand alone script

RandyBurton — Sun, 19 Nov 2017 23:12:58 GMT

In my latest test I was using "point_fc" for a folder name, with the same name used for a feature inside the geodatabase. I first noticed it when I moved a folder using the same name as a polygon feature that was part of a dataset into the directory with the file geodatabase. I was using describe to look at a feature's shapeType property - which is not a property when describing a folder!

Re: arcpy.describe in stand alone script

JoshuaBixby — Sat, 11 Dec 2021 17:36:29 GMT

What happens when you run the following outside of ArcGIS:

import arcpy
import os

fld = r"C:\tmp" # path to folder for running test

desc_fld = arcpy.CreateFolder_management(fld, "describe") 
arcpy.CreateFolder_management(desc_fld, "point_fc")
fgdb = arcpy.CreateFileGDB_management(desc_fld, "Default")
arcpy.CreateFeatureclass_management(fgdb, "point_fc", "POINT")
arcpy.CreateFeatureclass_management(fgdb, "line_fc", "POLYLINE")
arcpy.CreateFeatureclass_management(fgdb, "polygon_fc", "POLYGON")

arcpy.env.workspace = fgdb.getOutput(0)
for fc in arcpy.ListFeatureClasses("*"):
    desc = arcpy.Describe(fc)
    print "{} - {}".format(fc, desc.dataType)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

The code above recreates the folder and GDB structure you display in the original post

and the results for me are:

point_fc - FeatureClass
line_fc - FeatureClass
polygon_fc - FeatureClass
>>>‍‍‍‍

Re: arcpy.describe in stand alone script

RandyBurton — Mon, 20 Nov 2017 19:40:05 GMT

I did try this on a computer running ver 10.2.1, and describe gave the correct results. I will try again with the 10.5.0 version later today.

Re: arcpy.describe in stand alone script

RandyBurton — Sat, 11 Dec 2021 17:36:32 GMT

I am still getting the folder instead of the feature with 10.5.0. I added a few lines to check the working directory for Python and found if I change the cwd to the arcpy workspace then describe finds the feature. Perhaps there's a problem with the Python path/environment?

print "Arcpy: {}".format(arcpy.env.workspace)
print "Python: {}".format(os.getcwd())

for fc in arcpy.ListFeatureClasses("*"):
        desc = arcpy.Describe(fc)
        print "{} - {}".format(fc, desc.dataType)

os.chdir(arcpy.env.workspace)
print "\nNow: {}".format(os.getcwd())

for fc in arcpy.ListFeatureClasses("*"):
        desc = arcpy.Describe(fc)
        print "{} - {}".format(fc, desc.dataType)

# Output (using IDLE):

Arcpy: C:\Temp\describe\Default.gdb
Python: C:\Temp\describe
point_fc - Folder
line_fc - FeatureClass
polygon_fc - FeatureClass

Now: C:\Temp\describe\Default.gdb
point_fc - FeatureClass
line_fc - FeatureClass
polygon_fc - FeatureClass‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍