topic Re: Py.Problem in Python Questions

Py.Problem

Stanton_Coman — Sat, 14 Feb 2015 19:40:30 GMT

I am trying to write a code that will loop through a gdb listing all tables, rasters and featureclasses. It must also list all fields and their types in the featureclasses and print them. I can get everything to print properly with the exception of the ListField. Once I started playing with that command it went down hill. I think the problem lies in determining the dataset for the ListField to run through, I do not know how to tell the ListField to target every featureclass in the designated gdb.

import arcpy, os

### Set Workspace

##gdbpath = raw_input ('Enter File Full Pathname to Geodatabase')

##if arcpy.Exists(gdbpath):

## print 'GDB Found'

##else:

## exit('Invalid Pathname')

gdbpath = 'C:\Users\Stanton\Documents\GISProgramming\Database\Database\Corvallis.gdb'

arcpy.env.workspace = gdbpath

basepath = os.path.basename(gdbpath)

dirpath = os.path.dirname(gdbpath)

print '='*60

# GDB Name

print 'File Geodatabase Name: ' + basepath

#GDB Directory

print 'File Geodatabase Directory: ' + dirpath

# Number of Feature Classes

fcList = arcpy.ListFeatureClasses()

numberFC = len(fcList)

print 'Number of FeatureClasses: ' + str(numberFC)

# Number of Tables

tableList = arcpy.ListTables()

numberTables = len(tableList)

print 'Number of Tables: ' + str(numberTables)

# Number of Rasters:

rasterList = arcpy.ListRasters()

numberRasters = len (rasterList)

print 'Number of Rasters: ' + str(numberRasters)

print '='*60

#Table Names

tableName = tableList

if not tableName:

print 'Tables:'

print '\tNone\n'

else:

print 'Tables:'

for fc in tableName:

print '\t' + fc + '\n'

#Raster Names

rasterName = rasterList

if not rasterName:

print 'Rasters:'

print '\tNone\n'

else:

print 'Rasters:'

for fc in rasterName:

print '\t' + fc + '\n'

#FeaturClassNames and Field Names

fcName = fcList

if not fcName:

print 'FeatureClasses:'

print '\tNone\n'

else:

print 'FeatureClasses:'

dataset = gdbpath

fieldName = arcpy.ListFields(dataset,'*','All')

for fc in fcList:

print '\t' + fc + fieldName

Re: Py.Problem

DanPatterson_Retired — Sat, 14 Feb 2015 20:21:15 GMT

You have to use list fields on each featureclass not on a path as you currently have it. It should be inside your last loop. check the syntax in the list fields topic ArcGIS Help (10.2, 10.2.1, and 10.2.2)

Re: Py.Problem

Stanton_Coman — Sat, 14 Feb 2015 20:52:18 GMT

Dan,

Thank you for the reply. I understand that much but what I don't understand is how such a code would be written. I have little to no coding experience. How would I construct a code that would use the listfields on each individual featureclass in any designated gdb? Below is what I have written now with no success still.

#FeaturClassNames and Field Names

fcName = fcList

dataset = fc in gdbpath

fieldName = arcpy.ListFields(dataset,'*','ALL')

for field in fieldName:

fieldList = ("{0} ({1})".format(field.name, field.type))

if not fcName:

print 'FeatureClasses:'

print '\tNone\n'

else:

print 'FeatureClasses:'

for fc in fcList:

print '\t' + fc + fieldList

Re: Py.Problem

DanPatterson_Retired — Sat, 14 Feb 2015 20:59:17 GMT

Your code is still the same...you have to get a cycle through the featureclasses in the geodatabase, then for each featureclass, get a list of its fields, then for each field ... do something, like get its name etc.... in pseudocode since I don't have arcmap on this machine

featureclass_list....get a list of the feature classes

for each featureclass in featureclass_list:

list_fields in featureclass

for each field in list_fields

...do something

Re: Py.Problem

Stanton_Coman — Sat, 14 Feb 2015 21:35:09 GMT

Thanks Dan, that helped with my understanding of the problem. Still having trouble with the output.

#FeaturClassNames and Field Names

fcName = fcList

if not fcName:

print 'FeatureClasses:'

print '\tNone\n'

else:

print 'FeatureClasses:'

for fc in fcName:

fieldName = arcpy.ListFields(fc)

for field in fieldName:

print '\t' + str(fcName) + str((" {0} ({1})".format(field.name, field.type)))

and the result is

FeatureClasses:

[u'Address', u'Building', u'BoundaryLine', u'BoundaryPoly', u'Hydrant', u'Manhole', u'MapGrid', u'Parcel', u'ParkingMeters', u'Parks', u'Railroad', u'River', u'Schools', u'Sewer', u'StLights', u'WaterMeter', u'StPaved', u'Hydrant_buff', u'poop_buff', u'poop2_buff'] OBJECTID (OID)

and so on for each type of field.

Re: Py.Problem

DanPatterson_Retired — Sat, 14 Feb 2015 22:04:23 GMT

still no an ArcMap...but your last 2 lines need to be indented so that it will cycle through the fieldnames

for fc in fcNamd

fieldName...

for field in

I think

Re: Py.Problem

OwenEarley — Sat, 11 Dec 2021 12:56:47 GMT

Dan is correct about the indentation issue when looping through the field names. You want to output each field name for each feature class so you need to nest the fields loop within the feature class loop.

This partial example adds all of the field names to a python list and then outputs the feature class name followed by the fields:

fcName = fcList
if not fcName:
     print 'FeatureClasses:'
     print '\tNone\n'
else:
     print 'FeatureClasses:'
     for fc in fcName:
          fieldNames = arcpy.ListFields(fc)
          fieldList = []
          for field in fieldNames:
               fieldList.append(str((" {0} ({1})".format(field.name, field.type))))
          print str(fc) + ": " + ', '.join(fieldList)

The output looks like this:

FeatureClasses:

Richmond: OBJECTID (OID), RIVER_BASIN_NAME (String), SHAPE (Geometry), SHAPE_Length (Double), SHAPE_Area (Double)

Richmond_Strahler: OBJECTID (OID), SHAPE (Geometry), TOPOID (Integer), CLASSSUBTYPE (Integer), HYDRONAME (String), HYDRONAMETYPE (String), PERENNIALITY (SmallInteger), HIERARCHY (SmallInteger), HYDROTYPE (SmallInteger), CMA (String), COMMENTS (String), SUBCMA (String), STRAHLER (SmallInteger), SHAPE_Length (Double), SomeDate (Date)

Re: Py.Problem

Stanton_Coman — Fri, 06 Mar 2015 00:24:36 GMT

Dan and Owen thanks for the help!

The indentation made it run and from there I just had to play with the print statement to get it in the right format.