字段批量更新

import arcpy
from arcpy import env

env.workspace = "G:/domyy.gdb"
sl=4
for i in range(1,5):
#print i
wj="F"+str(i)
lyrfile = wj
result = int(arcpy.GetCount_management(lyrfile).getOutput(0))
#print result
inFeatures = wj
expression = result+”[a]"
arcpy.CalculateField_management(inFeatures, fieldName, expression, "VB", "")