This document discusses Python enhancements in ArcGIS including: 1. New features for working with feature classes and NumPy arrays such as converting feature classes to NumPy arrays. 2. Improved cursor functions for efficiently accessing and updating data in geodatabase tables and feature classes. 3. Updates to the arcpy.mapping module for applying symbology from layer files and exporting maps. 4. Brief mentions of new capabilities for add-ins and Python toolboxes.

1. Python in 10.1
Thom Mackey

2. Contents
• arcpy Enhancements
• Add-ins
• Python Toolboxes

3. FeatureClassToNumPyArray
import arcpy
import numpy
input = "C:/Data/ABSData.gdb/VIC_CCDs"
arr = arcpy.da.FeatureClassToNumPyArray(input,('CCD', 'pop_m', 'pop_f'))
# Sum the total population for males & females #
print(arr['pop_m'].sum())
print(arr['pop_f'].sum())
# Sum the female population for a particular CCD #
print(arr[arr['CCD'] == "2010101"]['pop_f'].sum())

4. FeatureClassToNumPyArray
import arcpy
import numpy
input = "C:/Data/ABSData.gdb/VIC_CCDs"
field1 = "INCOME"
field2 = "EDUCATION"
arr = arcpy.da.FeatureClassToNumPyArray(input, (field1, field2))
# Print correlation coefficients for the two fields
print(numpy.corrcoef((arr[field1],arr[field2])))

5. Improved Cursors
# Turn the contents of a GDB table into a Python list of lists
# Simple syntax & little code
with arcpy.da.SearchCursor(zonalstats_results_table,
["MINORITY","MAJORITY","MEAN"]) as tblcur:
results = [r for r in tblcur]

6. Improved Cursors
import arcpy
arcpy.env.workspace = "c:/data/output.gdb"
fc = "c:/data/base.gdb/roads"
fields = ("ROAD_TYPE", "BUFFER_DISTANCE")
with arcpy.da.UpdateCursor(fc, fields) as cursor:
# Update the field used in Buffer so the distance is based on road
# type. Road type is either 1, 2, 3 or 4. Distance is in meters.
for row in cursor:
row[1] = row[0] * 100
cursor.updateRow(row)

7. arcpy.mapping: update/apply symbology
import arcpy
mxd = arcpy.mapping.MapDocument(r"C:ProjectProject.mxd")
df = arcpy.mapping.ListDataFrames(mxd, "Census")[0]
lyr = arcpy.mapping.ListLayers(mxd, "StatePopulation", df)[0]
lyrFile = arcpy.mapping.Layer(r"C:ProjectLYRsPopulation.lyr")
arcpy.mapping.UpdateLayer(df, lyr, lyrFile, True)
if lyr.symbologyType == "GRADUATED_COLORS":
lyr.symbology.valueField = "POP2000"
lyr.symbology.classBreakValues = [250000, 999999, 4999999, 9999999, 35000000]
lyr.symbology.classBreakLabels = ["250,000 to 999,999", "1,000,000 to 4,999,999",
"5,000,000 to 9,999,999",
"10,000,000 to 35,000,000"]
arcpy.mapping.ExportToPDF(mxd, r"C:ProjectOutputStatePopulation.pdf")
del mxd, lyrFile

8. Add-Ins

9. Python Toolboxes