Listing feature classes from multiple feature datasets in GDB

Question

I am trying to list all feature classes from multiple datasets with single GDB. I have tried with below code

import arcpy
from arcpy import env
env.workspace = r"C:\GDB\Base.gdb"
fdlist = arcpy.ListDatasets("*","feature")
for fd in fdlist:
    print fd
    
    env.workspace = fd
    fclist = arcpy.ListFeatureClasses()
    for fc in fclist:
        print(fc)

Lists a few feature classes in first dataset then display below error.I have found some scripts that works for single dataset.

Traceback (most recent call last): File "C:\SOFTWARE\Arcpy\Arcpy_Script\List_fc.py", line 47, in for fc in fclist: TypeError: 'NoneType' object is not iterable

Answer 1

This will list all feature classes, inside a dataset and just sitting in the root of the geodatabase. It works with empty datasets. It works with an empty root. If you don't want to search the root, just leave the second part out.

import arcpy
from arcpy import env
env.workspace = r"C:\GDB\Base.gdb"

# list all FC in each dataset
fdlist = arcpy.ListDatasets("*","Feature")
for fd in fdlist:
    print("DS:", fd)
    fclist = arcpy.ListFeatureClasses("*","All",fd)
    for fc in fclist:
        print("\tFC:", fc)
    
# list all FC in root of GDB
fclist = arcpy.ListFeatureClasses()
for fc in fclist:
    print("FC:", fc)

Answer 2

You can limit the ListFeatureClasses to a feature dataset eg arcpy.ListFeatureClasses(feature_dataset=fd).

Not sure if the env.workspace=fd is working maybe it only works to the gdb level. See https://desktop.arcgis.com/en/arcmap/latest/analyze/arcpy-functions/listfeatureclasses.htm

Answer 3

Listing and finding data sets is best accomplished using Walk - ArcGIS Pro | Documentation. ArcPy DA Walk mimics the behavior of Python's os.walk, and doesn't rely on setting workspace environments, which is both slow and prone to mistakes.

It appears this question is about listing all the feature classes in a geodatabase, both stand-alone and those in datasets. This is easily accomplished with ArcPy DA Walk:

import arcpy
import os

# Set geodatabase
input_gdb = # path to geodatabase

# Get list of polygon feature classes in GDB
walk = arcpy.da.Walk(input_gdb, datatype="FeatureClass")
fc_list = [
    os.path.join(root, feature_class)
    for root, data_sets, feature_classes in walk
    for feature_class in feature_classes
]

print(*fc_list, sep="\n")