topic Re: ModelBuilder Calculate Field in ModelBuilder Questions

ModelBuilder Calculate Field

WadeGivens — Sun, 12 Dec 2021 09:17:23 GMT

I'm using ModelBuilder to create a new field ([cat]) that will contain category values based on range criteria of another field ([yield]). I would like to use the Python parser. HEre is what I have so far in the Pre-Logic Script Code:

def Reclass(yield) :
  if (yield <=140) :
    return "Low"
  elif (yield > 140 and yield <= 180) :
    return "Average"
  elif (yield > 180) :

In the expression block I have cat = Reclass(!cat!)

I get a red "X" in the calculate Field dialog stating there is a parse error on line 1. Any ideas as to what I'm doing wrong?

Thanks,

Re: ModelBuilder Calculate Field

TerrySilveus — Sun, 12 Dec 2021 09:17:25 GMT

you can't use yield it is a reserved word

also what you posted doesn't see complete
try this

def Reclass(x):
  if (x <=140):
    return "Low"
  elif (x > 140 and x <= 180):
    return "Average"
  elif (x > 180):
    return "High"

Re: ModelBuilder Calculate Field

BruceNielsen — Thu, 01 Mar 2012 12:59:58 GMT

Your expression block should be:

cat = Reclass(!yield!)

Otherwise you'd be trying to read an integer from a string field.

Re: ModelBuilder Calculate Field

TerrySilveus — Thu, 01 Mar 2012 18:13:54 GMT

Your expression block should be:
cat = Reclass(!yield!)
Otherwise you'd be trying to read an integer from a string field.

"Yield" within the function still needs to be changed as well, but you are right you can't pass a string when the function is looking for a number. Therefore cat = Reclass(!cat!) should be changed to cat = Reclass(!nameOfFieldwithNumbericValue!) unless cat is the field with the numeric value; in that case it should be nameOfFieldWithStringValue = Reclass(!Cat!)

Re: ModelBuilder Calculate Field

TedKowal — Sun, 12 Dec 2021 09:17:28 GMT

or perhaps

cat = Reclass(int(!cat!))   # --- If you need to use the cat value and overwrite the string number with text
                            # --- Then you would also have to account for possible non numbers text in the Reclass def?‍‍‍‍‍‍‍‍‍‍

Re: ModelBuilder Calculate Field

curtvprice — Sat, 29 Oct 2016 01:53:00 GMT

The expression for the Calculate Field tool should simply be (if "cat" is your field name). CAT is also then entered in the Field argument to Calculate Field.

Ted is correct that you'd want to account for non-covered fields. Seems to me it would be safer to create a new field and calculate to that in case something goes wrong.

Reclass(!CAT!)‍‍