[GIS] Using ArcPy to multiply fields in attribute table

Question

I am trying to identify a method to multiply 2 fields in the same attribute table and write the product of the calculation into an added field. The code creates the empty fields, now I just want to understand how to use arcpy to run a field calculation.

This is what I have so far:

# Set the local parameters
inFeatures = "ESR_States"
joinField = "STID"
joinTable = "ESR_Weather"
# Join two feature classes by the STID field 
arcpy.JoinField_management (inFeatures, joinField, joinTable, joinField)
# Add fields to ESR_States
fieldName1 = "POT_PROD"
fieldName2 = "POT_CONSU"
fieldName3 = "SELF_SUS"
fieldName4 = "FUTURE_POP"
arcpy.AddField_management(inFeatures, fieldName1, "LONG")
arcpy.AddField_management(inFeatures, fieldName2, "LONG")
arcpy.AddField_management(inFeatures, fieldName3, "LONG")
arcpy.AddField_management(inFeatures, fieldName4, "LONG")
arcpy.CalculateField_management()

Answer 1

I think the easiest way to learn "how to use ArcPy to run a field calculation" is to:

• Go to the Search window and find the Calculate Field tool
• Open its tool dialog
• Configure a test calculation and run the tool
• Open the Geoprocessing | Results window
• Right-click on the Calculate Field run that you see there
• Choose Copy As Python Snippet
• Paste the code snippet into your script
• Modify the code thus pasted, if necessary

If you need more help with using the Field Calculator from ArcPy than this then I recommend reviewing our self-assembling FAQ on ArcPy and the Field Calculator.