How to Introspect a Describe "Object"

ThomasLaxson

Though the documentation refers to a "Describe object", it must be some sort of C class (apparently via the arcgisscripting.create function), instead of a Python class. The standard Python introspection methods don't turn up much information (see below).

If one wishes to summarize all the known info of a dataset, how might one dynamically identify which properties apply to the current instance--without writing a long series of if statements and/or going through all the potential properties?

For reference: given a variable named "desc" returned from a call to arcpy.Describe, here are the results of some inspection and introspection operations:

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> type<SPAN class="punctuation token">(</SPAN>desc<SPAN class="punctuation token">)</SPAN>
<SPAN class="operator token"><</SPAN>type <SPAN class="string token">'geoprocessing describe data object'</SPAN><SPAN class="operator token">></SPAN>

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> dir<SPAN class="punctuation token">(</SPAN>desc<SPAN class="punctuation token">)</SPAN>
<SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">]</SPAN>

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> desc<SPAN class="punctuation token">.</SPAN>__name__
<SPAN class="string token">'Describe Object'</SPAN>

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> desc<SPAN class="punctuation token">.</SPAN>__class__
Traceback <SPAN class="punctuation token">(</SPAN>most recent call last<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>&nbsp; 
 File <SPAN class="string token">"<interactive input>"</SPAN><SPAN class="punctuation token">,</SPAN> line <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">in</SPAN> <SPAN class="operator token"><</SPAN>module<SPAN class="operator token">></SPAN>
AttributeError<SPAN class="punctuation token">:</SPAN> DescribeData<SPAN class="punctuation token">:</SPAN> Method __class__ does <SPAN class="operator token">not</SPAN> exist

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> desc<SPAN class="punctuation token">.</SPAN>__repr__
Traceback <SPAN class="punctuation token">(</SPAN>most recent call last<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>&nbsp; 
 File <SPAN class="string token">"<interactive input>"</SPAN><SPAN class="punctuation token">,</SPAN> line <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">in</SPAN> <SPAN class="operator token"><</SPAN>module<SPAN class="operator token">></SPAN>
AttributeError<SPAN class="punctuation token">:</SPAN> DescribeData<SPAN class="punctuation token">:</SPAN> Method __repr__ does <SPAN class="operator token">not</SPAN> exist

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> isinstance<SPAN class="punctuation token">(</SPAN>desc<SPAN class="punctuation token">,</SPAN> object<SPAN class="punctuation token">)</SPAN>
<SPAN class="token boolean">True</SPAN>

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> desc<SPAN class="punctuation token">.</SPAN>__dict__
Traceback <SPAN class="punctuation token">(</SPAN>most recent call last<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>&nbsp; 
 File <SPAN class="string token">"<interactive input>"</SPAN><SPAN class="punctuation token">,</SPAN> line <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">in</SPAN> <SPAN class="operator token"><</SPAN>module<SPAN class="operator token">></SPAN>
AttributeError<SPAN class="punctuation token">:</SPAN> DescribeData<SPAN class="punctuation token">:</SPAN> Method __dict__ does <SPAN class="operator token">not</SPAN> exist

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> help<SPAN class="punctuation token">(</SPAN>desc<SPAN class="punctuation token">)</SPAN>
Help on geoprocessing describe data object object<SPAN class="punctuation token">:</SPAN>
Describe Object <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">class</SPAN> <SPAN class="token class-name">geoprocessing</SPAN> describe data object<SPAN class="punctuation token">(</SPAN>object<SPAN class="punctuation token">)</SPAN>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> <SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN>inspect<SPAN class="punctuation token">.</SPAN>getmodule<SPAN class="punctuation token">(</SPAN>desc<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
None

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> inspect<SPAN class="punctuation token">.</SPAN>getclasstree<SPAN class="punctuation token">(</SPAN>desc<SPAN class="punctuation token">)</SPAN>
Traceback <SPAN class="punctuation token">(</SPAN>most recent call last<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>&nbsp; 
 File <SPAN class="string token">"<interactive input>"</SPAN><SPAN class="punctuation token">,</SPAN> line <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">in</SPAN> <SPAN class="operator token"><</SPAN>module<SPAN class="operator token">></SPAN>&nbsp; 
 File <SPAN class="string token">"C:\Python27\ArcGISx6410.4\Lib\inspect.py"</SPAN><SPAN class="punctuation token">,</SPAN> line <SPAN class="number token">726</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">in</SPAN> getclasstree&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> c <SPAN class="keyword token">in</SPAN> classes<SPAN class="punctuation token">:</SPAN>
TypeError<SPAN class="punctuation token">:</SPAN> <SPAN class="string token">'geoprocessing describe data object'</SPAN> object <SPAN class="keyword token">is</SPAN> <SPAN class="operator token">not</SPAN> iterable

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> inspect<SPAN class="punctuation token">.</SPAN>getmro<SPAN class="punctuation token">(</SPAN>desc<SPAN class="punctuation token">)</SPAN>
Traceback <SPAN class="punctuation token">(</SPAN>most recent call last<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>&nbsp; 
 File <SPAN class="string token">"<interactive input>"</SPAN><SPAN class="punctuation token">,</SPAN> line <SPAN class="number token">1</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">in</SPAN> <SPAN class="operator token"><</SPAN>module<SPAN class="operator token">></SPAN>&nbsp; 
 File <SPAN class="string token">"C:\Python27\ArcGISx6410.4\Lib\inspect.py"</SPAN><SPAN class="punctuation token">,</SPAN> line <SPAN class="number token">346</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">in</SPAN> getmro
&nbsp;&nbsp;&nbsp; _searchbases<SPAN class="punctuation token">(</SPAN>cls<SPAN class="punctuation token">,</SPAN> result<SPAN class="punctuation token">)</SPAN>
 File <SPAN class="string token">"C:\Python27\ArcGISx6410.4\Lib\inspect.py"</SPAN><SPAN class="punctuation token">,</SPAN> line <SPAN class="number token">337</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">in</SPAN> _searchbases
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> base <SPAN class="keyword token">in</SPAN> cls<SPAN class="punctuation token">.</SPAN>__bases__<SPAN class="punctuation token">:</SPAN>
AttributeError<SPAN class="punctuation token">:</SPAN> DescribeData<SPAN class="punctuation token">:</SPAN> Method __bases__ does <SPAN class="operator token">not</SPAN> exist‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

JoshuaBixby

I think arcgisscripting was introduced with ArcGIS 9.0 and describe() has been around since the very beginning.  In my mind, arcgisscripting wasn't so much a Python package as much as a Python wrapper for a COM-based package, i.e., arcgisscripting wasn't very Pythonic.  The Describe Object has to be one of the least Pythonic objects in the entire ArcPy package, one of the reasons being what you have pointed out about lack of inspection and introspection.

This raises the question of, "why hasn't Esri made the Describe Object more Pythonic with any of the 9+ major releases since ArcGIS 9.0?"  Unfortunately, I don't have an answer, not even a bad one.  Part of it might have to do with "why fix what isn't broken" and another factor might be the nested hierarchy/inheritance of how the Describe Object works under the hood, but I am just speculating.

Although inspection and introspection of the Describe Object itself is non-existent, the documentation does lay it all out so it isn't a complete guessing game as to which objects support which property.  The following code scrapes the Esri documentation to extract all of the property types and properties from the documentation:

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> <SPAN class="keyword token">import</SPAN> bs4
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> <SPAN class="keyword token">import</SPAN> urllib2
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> <SPAN class="keyword token">from</SPAN> collections <SPAN class="keyword token">import</SPAN> Iterable
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> 
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> site <SPAN class="operator token">=</SPAN> <SPAN class="string token"><SPAN>"</SPAN><A class="jive-link-external-small" href="https://community.esri.com/external-link.jspa?url=http%3A%2F%2Fdesktop.arcgis.com" target="_blank">http://desktop.arcgis.com</A><SPAN>"</SPAN></SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> path <SPAN class="operator token">=</SPAN> <SPAN class="string token">"/en/arcmap/latest/analyze/arcpy-functions/describe.htm"</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> desc_props <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">]</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> 
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> f <SPAN class="operator token">=</SPAN> urllib2<SPAN class="punctuation token">.</SPAN>urlopen<SPAN class="punctuation token">(</SPAN>site <SPAN class="operator token">+</SPAN> path<SPAN class="punctuation token">)</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> soup <SPAN class="operator token">=</SPAN> bs4<SPAN class="punctuation token">.</SPAN>BeautifulSoup<SPAN class="punctuation token">(</SPAN>f<SPAN class="punctuation token">.</SPAN>read<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> seealso <SPAN class="operator token">=</SPAN> soup<SPAN class="punctuation token">.</SPAN>find<SPAN class="punctuation token">(</SPAN>class_<SPAN class="operator token">=</SPAN><SPAN class="string token">"seealso bulleted"</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> seealso_paths <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">(</SPAN>a<SPAN class="punctuation token">.</SPAN>find<SPAN class="punctuation token">(</SPAN>text<SPAN class="operator token">=</SPAN><SPAN class="token boolean">True</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">,</SPAN> a<SPAN class="punctuation token">[</SPAN><SPAN class="string token">'href'</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">)</SPAN> 
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> a <SPAN class="keyword token">in</SPAN> seealso<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"a"</SPAN><SPAN class="punctuation token">,</SPAN> href<SPAN class="operator token">=</SPAN><SPAN class="token boolean">True</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN> <SPAN class="punctuation token">]</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN> 
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> 
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> <SPAN class="keyword token">for</SPAN> type<SPAN class="punctuation token">,</SPAN> path <SPAN class="keyword token">in</SPAN> seealso_paths<SPAN class="punctuation token">:</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp; f <SPAN class="operator token">=</SPAN> urllib2<SPAN class="punctuation token">.</SPAN>urlopen<SPAN class="punctuation token">(</SPAN>site <SPAN class="operator token">+</SPAN> path<SPAN class="punctuation token">)</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp; soup <SPAN class="operator token">=</SPAN> bs4<SPAN class="punctuation token">.</SPAN>BeautifulSoup<SPAN class="punctuation token">(</SPAN>f<SPAN class="punctuation token">.</SPAN>read<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp; proptbl <SPAN class="operator token">=</SPAN> soup<SPAN class="punctuation token">.</SPAN>find<SPAN class="punctuation token">(</SPAN>class_<SPAN class="operator token">=</SPAN><SPAN class="string token">"arcpyclass_proptbl"</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">if</SPAN> proptbl<SPAN class="punctuation token">:</SPAN> 
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; proptbl<SPAN class="punctuation token">.</SPAN>thead<SPAN class="punctuation token">.</SPAN>extract<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; desc_props <SPAN class="operator token">+=</SPAN> <SPAN class="punctuation token">(</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; type<SPAN class="punctuation token">,</SPAN> tuple<SPAN class="punctuation token">(</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; row<SPAN class="punctuation token">.</SPAN>td<SPAN class="punctuation token">.</SPAN>find<SPAN class="punctuation token">(</SPAN>text<SPAN class="operator token">=</SPAN><SPAN class="token boolean">True</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> row <SPAN class="keyword token">in</SPAN> proptbl<SPAN class="punctuation token">(</SPAN><SPAN class="string token">"tr"</SPAN><SPAN class="punctuation token">,</SPAN> recursive<SPAN class="operator token">=</SPAN><SPAN class="token boolean">False</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">)</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">,</SPAN>
<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN> 
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> <SPAN class="comment token"># Number of property categories/types</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> <SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN>len<SPAN class="punctuation token">(</SPAN>desc_props<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="number token">31</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> <SPAN class="comment token"># Total number of properties</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> <SPAN class="keyword token">print</SPAN><SPAN class="punctuation token">(</SPAN>sum<SPAN class="punctuation token">(</SPAN><SPAN class="number token">1</SPAN> <SPAN class="keyword token">for</SPAN> type<SPAN class="punctuation token">,</SPAN> props <SPAN class="keyword token">in</SPAN> desc_props <SPAN class="keyword token">for</SPAN> prop <SPAN class="keyword token">in</SPAN> props<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="number token">248</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

As you can see, there are 31 property categories or types and 248 properties, although no one object supports/has all 248 properties.  As of ArcGIS 10.5, the categories and types from the code above are:

Describe Object Properties:     baseName     catalogPath     children     childrenExpanded     dataElementType     dataType     extension     file     fullPropsRetrieved     metadataRetrieved     name     path ArcInfo Workstation Item:     alternateName     isIndexed     isPseudo     isRedefined     itemType     numberDecimals     outputWidth     startPosition     width ArcInfo Workstation Table:     itemSet CAD Drawing Dataset Properties:     is2D     is3D     isAutoCAD     isDGN Cadastral Fabric Properties:     bufferDistanceForAdjustment     compiledAccuracyCategory     defaultAccuracyCategory     maximumShiftThreshold     multiGenerationEditing     multiLevelReconcile     pinAdjustmentBoundary    pinAdjustmentPointsWithinBoundary     surrogateVersion     type     version     writeAdjustmentVectors Coverage FeatureClass Properties:     featureClassType     hasFAT     topology Coverage Properties:     tolerances Dataset Properties:     canVersion     changeTracked     datasetType     DSID     extent     isArchived     isVersioned     MExtent     spatialReference     ZExtent Editor Tracking Properties:     editorTrackingEnabled     creatorFieldName     createdAtFieldName     editorFieldName     editedAtFieldName     isTimeInUTC FeatureClass Properties:     featureType     hasM     hasZ     hasSpatialIndex     shapeFieldName     shapeType GDB FeatureClass Properties:     areaFieldName     geometryStorage     lengthFieldName     representations GDB Table Properties:     aliasName     defaultSubtypeCode     extensionProperties     globalIDFieldName     hasGlobalID     modelName     rasterFieldName     relationshipClassNames     subtypeFieldName     versionedView Geometric Network Properties:     featureClassNames     networkType     orphanJunctionFeatureClassName LAS Dataset Properties:     constraintCount     fileCount     hasStatistics     needsUpdateStatistics     pointCount     usesRelativePath

Layer Properties:     dataElement     featureClass     FIDSet     fieldInfo     layer     nameString     table     whereClause Mosaic Dataset Properties:     allowedCompressionMethods     allowedFields     allowedMensurationCapabilities     allowedMosaicMethods     applyColorCorrection     blendWidth     blendWidthUnits     cellSizeToleranceFactor     childrenNames     clipToBoundary     clipToFootprint     defaultCompressionMethod     defaultMensurationCapability     defaultMosaicMethod     defaultProcessingTemplate     defaultResamplingMethod     dimensionAttributes     dimensionNames     dimensionValues     endTimeField     footprintMayContainNoData     GCSTransforms     isMultidimensional     JPEGQuality     LERCTolerance     maxDownloadImageCount     maxDownloadSizeLimit     maxRastersPerMosaic     maxRecordsReturned     maxRequestSizeX     maxRequestSizeY     minimumPixelContribution     mosaicOperator     multidimensionalInfo     orderBaseValue     orderField     processingTemplates     rasterMetadataLevel     referenced     sortAscending     startTimeField     timeValueFormat     useTime     variableAttributes     variableNames     viewpointSpacingX     viewpointSpacingY Network Analyst:     network     nameString     solverName     impedance     accumulators     restrictions     ignoreInvalidLocations     uTurns     useHierarchy     hierarchyAttribute     hierarchyLevelCount     maxValueForHierarchyX     locatorCount     locators     findClosest     searchTolerance     excludeRestrictedElements     solverProperties     children     parameterCount     parameters Network Dataset Properties:     attributes     catalogPath     defaultTravelModeName     directions     edgeSources     elevationModel     historicalTrafficData     isBuildable     junctionSources     liveTrafficData     networkType     optimizations     sources     supportsDirections     supportsHistoricalTrafficData     supportsLiveTrafficData     supportsTurns     systemJunctionSource     timeZoneAttributeName     timeZoneTableName     trafficSupportType     turnSources

Prj File Properties:     spatialReference Raster Band Properties:     height     isInteger     meanCellHeight     meanCellWidth     noDataValue     pixelType     primaryField     tableType     width Raster Catalog Properties:     rasterFieldName Raster Dataset Properties:     bandCount     compressionType     format     permanent     sensorType RecordSet and FeatureSet Properties:     json     pjson RelationshipClass Properties:     backwardPathLabel     cardinality     classKey     destinationClassKeys     destinationClassNames     forwardPathLabel     isAttachmentRelationship     isAttributed     isComposite     isReflexive     keyType     notification     originClassNames     originClassKeys     relationshipRules RepresentationClass Properties:     overrideFieldName     requireShapeOverride     ruleIDFieldName Schematic Diagram Properties:     diagramClassName Table Properties:     hasOID     OIDFieldName     fields     indexes TableView Properties:     table     FIDSet     fieldInfo     whereClause     nameString Tin Properties:     fields     hasEdgeTagValues     hasNodeTagValues     hasTriangleTagValues     isDelaunay     ZFactor Topology Properties:     clusterTolerance     featureClassNames     maximumGeneratedErrorCount     ZClusterTolerance Workspace Properties:     connectionProperties     connectionString     currentRelease     domains     release     workspaceFactoryProgID     workspaceType

Instead of trying to work through all of the rules for which properties apply to what kind of object, I have always found just testing all of them is quite fast.  That way, you know exactly which properties apply even if they aren't all documented.

Instead of using a try:except block, just use getattr() with a default value of None.  For a file geodatabase polyline feature class, I get 56 properties that return some kind of value.