I am trying to populate a field with a L/R bank designation based on a route measure (as part of a larger script), but I am struggling. I have a shapefile created (tir_pts_lyr), I have a blank column (L_R_Bank), I have the measure value column (M_off_str). So if the measure value is negative, I want "L_R_Bank" to be populated with an "L", if the measure is positive, an "R", and if zero, a "C".
I'm trying to use the sample codeblocks in the ArcHelp, but they are lacking in detail for my knowledge level. I have no clue what to put in the expression field for getClass and how the next codeblock line relates to that. Any hints for a newbie.
#calc left/right bank using M-distance measure # Set local variables inTable = "tir_pts_lyr" fieldName = "L_R_Bank" expression = "getClass(float(!SHAPE.M_Off_str!))" codeblock = """def getClass(M_Off_str): if M_Off_str < 0: return "L" if M_Off_str > 0: return "R" else: return "C" """ #Execute CalculateField arcpy.CalculateField_management(inTable, fieldName, expression, "PYTHON", codeblock)