Arcpy 隨機選取部分要素並導出

# Import system modules
import arcpy, os, time
import random
from arcpy import env

print '程序開始：' + str(time.ctime())  
# Set environment settings
env.workspace = "D:\pythonlearint.gdb"
 
# Set local variables
inFeatures = "畢節市矢量圖1228"
fieldName1 = "RD"
fieldPrecision = 9
fieldAlias = "隨機數字"

# Execute AddField
arcpy.AddField_management(inFeatures, fieldName1, "DOUBLE", fieldPrecision, "", "",
                          fieldAlias, "NULLABLE")

field1 = "RD"
cursor = arcpy.UpdateCursor(inFeatures)
for row in cursor:
    # 隨機賦值
    row.setValue(field1, random.random())
    cursor.updateRow(row)


#導出選擇的數據集
arcpy.MakeFeatureLayer_management(inFeatures, "lyr") 
arcpy.SelectLayerByAttribute_management("lyr", "NEW_SELECTION", ' "RD" < 0.05 ')

 
# Write the selected features to a new featureclass
arcpy.CopyFeatures_management("lyr", "RD_Train")

print '程序結束：' + str(time.ctime())