Here is the code to populate an attribute in the attribute table with a 0 or 1 for 5% of your records. If you want to select 5% of those records that have some other attribute value, then just insert a select by attribute where I have it marked, then only 5% of the selected records will be assigned a 1.'''Selects a random number of records from a feature class and populates a
user-defined field with either a 1 or a 0 based on the input parameters. For
example, if percent_to_include is set to 5, then a random ~5 percent of the
records will be asigned a value of 1, the rest a value of 0.
'''
try:
import operator, os, random, traceback, sys, arcpy
##Path to the feature class.
fc = r"Z:\GISpublic\GerryG\RestorationandMitigationConcept\20110425IvyPlotMonitoring\transects.shp"
##The attribute to populate with 1 or 0...
attribute = r"issample"
##The percent threshold to include as a random selection.
percent_to_include = 5
##INSERT YOUR SELECT BY ATTRIBIUTE HERE
uc = arcpy.UpdateCursor(fc)
for row in uc:
x = random.random() * 100
#arcpy.AddMessage(x)
if x <= percent_to_include:
row.setValue(attribute, 1)
else:
row.setValue(attribute, 0)
uc.updateRow(row)
print "Done"
except:
tb = sys.exc_info()[2]
tbinfo = traceback.format_tb(tb)[0]
pymsg = "PYTHON ERRORS:\nTraceback info:\n" + tbinfo + "\nError Info:\n" + str(sys.exc_info()[1])
print pymsg + "\n"
