topic Re: Conditional replace function in Field Calculator in Python Questions

Conditional replace function in Field Calculator

BenjaminYoung — Wed, 20 Jun 2012 12:11:23 GMT

I'm trying to write an expression that will allow me to change the text of a string field based on it's values.

Here's what I have so far.

----

Dim output as String

IF [DUPLICATE] = "0"
THEN
output = replace( [DUPLICATE], "0", "CATEGORY 1")
end if

IF [DUPLICATE] = "1"
THEN
output = replace( [DUPLICATE], "1", "CATEGORY 2")
end if

IF [DUPLICATE] = "2"
THEN
output = replace( [DUPLICATE], "2", "CATEGORY 3")
end
----

Any help would be appreciated.

Re: Conditional replace function in Field Calculator

JimCousins — Wed, 20 Jun 2012 13:21:28 GMT

A single "=" is an assignment. In order to do a comparison, use "==" a double equal sign. You could also nest these individual if statements with:
if [DUPLICATE] == "0":
output = replace( [DUPLICATE], "0", "CATEGORY 1")
elif [DUPLICATE] == "1":
output = replace( [DUPLICATE], "1", "CATEGORY 2")
....

Re: Conditional replace function in Field Calculator

BenjaminYoung — Wed, 20 Jun 2012 17:21:48 GMT

Thanks but still not working. Is it something with the

if [DUPLICATE] == "0":
output = replace( [DUPLICATE], "0", "CATEGORY 1")

?

Tried that line by itself and returned an error.

Re: Conditional replace function in Field Calculator

JasonScheirer — Wed, 20 Jun 2012 17:23:41 GMT

In the Field Calc, need to do !DUPLICATE! and not [DUPLICATE] in Python.

Re: Conditional replace function in Field Calculator

JimCousins — Wed, 20 Jun 2012 19:53:06 GMT

Also be mindful of indentation. My earlier post didn't show correct indentation after the if statement. Apologies for that.

Re: Conditional replace function in Field Calculator

DarrenWiens2 — Sat, 11 Dec 2021 16:16:35 GMT

Firstly, you need to decide if you want to use VBScript or Python. You started with almost functional VBScript and have been slowly drifting into functional Python.

PYTHON:
In the expression box:

func(!DUPLICATE!)

Then, in the codeblock:

def func(dup):
    if dup == "0":
        return "CATEGORY 1"
    elif dup == "1":
        return "CATEGORY 2"

VBSCRIPT:
In the expression box:

result

Codeblock:

if [DUPLICATE] = 0 then
  result = "CATEGORY 1"
elseif [DUPLICATE] = 1 then
  result = "CATEGORY 2"
else
  result = [DUPLICATE]
end if