1. arcpy.Describe and arcpy.List*

2. Describing objects
ArcGIS interacts with a number of types of objects arcpy.Describe(object) exposes object properties that can be used in Python to control program flow, tool parameter values, etc. of geoprocessing scripts e.g. Clip all polyline feature classes in a workspace.

3. gp.List*  Python list of objects ArcGIS 10
Overview
gp.Describe(object)
 Describe object
gp.List*  Python list of objects
ArcGIS 10
arcpy.Describe(object)
arcpy.List*

4. Evolution Describe Object Properties
An example of how Python is evolving
with ArcGIS
9.2
9.3

5. Describing data in 10.x

6. Describe Example (feature class)
… if you plan to do multiples in same workspace

7. Describe a Feature Class

8. Describe a Geodatabase
some are case sensitive, others not
arcpy.env.workspace is

9. Fields in a Feature Class via Describe
ArcGIS 8.x, 9.x
ArcGIS 10

10. Describe a Raster

11. List functions Scripts allow you to iterate through lists
arcpy provides many list functions that create lists of objects
e.g. For each feature class in a given workspace, create a report that shows how many are point, line, and polygon (uses ListFeatureClasses and Describe)

12. Lists of Objects in Geoprocessing OMD

13. List*: Python List (i.e. returns a Python List)
Listing Data
List*: Python List (i.e. returns a Python List)
Know number of * in a Python list
Use a for loop

14. ListFeatureClasses([wildCard], [FeatureType])

15. ListFeatureClasses examples

16. ListFields(pInputValue, [wild card], [FieldType])
Same Field object as each Field object in list that is returned by Fields property of the Describe Object

17. ListFields examples

18. os.walk(top, topdown=True, onerror=None, followlinks=False)

19. os.walk() simple example

20. os.walk() not-so-simple example
Find all Flash videos (SWF) in the entire tree under a given root folder
If the SWF file has the “slide”, and not “group”, as part of its name convert the first frame of the video to a JPG with the name of the SWF

21. Dependencies Python for Windows Extensions
Interfacing with Windows, Windows applications & libraries
SWF To Image ActiveX library

22. os.walk() not-so-simple example