# -*- coding: utf-8 -*-
import arcpy,os
import sys

shppath = r"d:/gisdata/QSDK/2.shp"  #引号内为你shp路径及位置
tempDic = {}
maxArea = 0.0
preNumber = 0.0
searchCursor  = arcpy.SearchCursor(shppath)
while True:
    currentRow = searchCursor.next()
    if not currentRow:
	    break
    currentNum = currentRow.getValue("BSM")  #第一步中的唯一值字段
    area = currentRow.getValue("area")  #面积字段
    if preNumber!=currentNum:
        maxArea = 0.0
    if area>maxArea:
        maxArea = area
        tempDic.update({currentNum:maxArea})
    preNumber = currentNum
del searchCursor

print "tempDic is ok "


updateCursor  = arcpy.UpdateCursor(shppath)
while True:
    currentRow = updateCursor.next()
    if not currentRow:
	    break
    currentNum = currentRow.getValue("BSM")   #第一步中的唯一值字段
    area = currentRow.getValue("area")   #面积字段
    if tempDic.has_key(currentNum):
        if area==tempDic.get(currentNum):
            currentRow.setValue("最大值","最大值")
        else:
            currentRow.setValue("最大值","非最大值")
        updateCursor.updateRow(currentRow)
del updateCursor   
print "program is end " 
