topic Re: If/Else do nothing in Python Questions

If/Else do nothing

City_of_Greenville__SCGIS — Thu, 17 May 2018 21:01:15 GMT

I'm trying to write a simple if/else statement where if the value isn't found, Arcmap keeps the current field value. I've tried using the default python command of pass but it still overwrites the values to null. Any advice? Code from codeblock below.

def reclass(mystring):
if (mystring == 'C-4'):
return 'Central Business District'

else:

pass

Scott

Re: If/Else do nothing

JoshuaBixby — Sat, 11 Dec 2021 22:10:26 GMT

In Python, the default for a function is to return None, which will get converted to NULL in your case. Try:

def reclass(mystring):
      if (mystring == 'C-4'):
           return 'Central Business District'
      else:
           return mystring‍‍‍‍‍

Re: If/Else do nothing

City_of_Greenville__SCGIS — Fri, 18 May 2018 15:03:28 GMT

I'm actually running it against a different field though so I don't want it to just return mystring, I should've stated that.

Here's what I want:

The field being calculated is field2

reclass(!field1!)

def reclass(mystring): if (mystring == 'C-4'): return 'Central Business District' else: return the existing value in field2 or just do nothing to field2

Does that make sense? Can I just define field2 in the codeblock and say if else return the value for field2?

Scott

Re: If/Else do nothing

JoshuaBixby — Sat, 11 Dec 2021 22:10:29 GMT

The better way is to pass both fields to the function:

def reclass(f1, f2):
      if (f1 == 'C-4'):
           return 'Central Business District'
      else:
           return f2‍‍‍‍‍

and call it using:

reclass(!field1!, !field2!)‍

Re: If/Else do nothing

City_of_Greenville__SCGIS — Fri, 18 May 2018 16:07:43 GMT

Perfect, this is what I was looking for.

Scott