topic using the field calculator with python in Python Questions

using the field calculator with python

LeifJohnson — Wed, 27 Jul 2016 18:41:10 GMT

Hello,

So i am trying to use the field calculator using python to determine the input for the field. So for example my table has 2 fields(both text fields(one of the fields would be empty at this point)), i would like the code to say If field one is "String 1" then put in field 2 "string 2". Basically i want it to check the value of field one and if it matches the string i am looking for then i want it to write another string that i decide in the code to write. I was wondering if someone had a template of a similar code that i can look at to get an idea on how to write it. Preferable in python but i think VB works also. Thanks in advance

Re: using the field calculator with python

DanPatterson_Retired — Wed, 27 Jul 2016 21:58:18 GMT

the best bet would be to either show the code you are trying to implement or show the field calculator syntax you are using since your description is a bit of both

Re: using the field calculator with python

DarrenWiens2 — Wed, 27 Jul 2016 22:04:54 GMT

See the third example on this page, which uses if-then logic in a code block: Calculate Field—Help | ArcGIS for Desktop

Re: using the field calculator with python

FC_Basson — Sun, 12 Dec 2021 04:43:10 GMT

So you basically want to calculate Field 2 based on the value in Field 1

Your Python code block can look like this:

def calcfield(field1):
   val = ""
   if field1 == "test":
      val = "string 2"
   else:
      val = "other string"
 return val‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

And the field calculation expression:

Field2 =

calcfield(!MyField!)‍