Conditioning labels

[Ulises]

Hi everyone,

I'm trying to define an expression for labeling parcel polygons in ArcMap.  The feature class has 3 attributes of interest: CATEGORIA, NUM_CATASTRO, and PARCEL_SP.  If CATEGORIA (integer field with subtypes defined) is not 0 (N/A), then label the polygon with the value in PARCEL_SP, otherwise label with NUM_CATASTRO.  I'm not a programmer and I'm just starting with Python so I'm not sure what is missing.  So far I have...

def FindLabel (  [CATEGORIA],[NUM_CATASTRO], [PARCEL_SP] ):
  if [CATEGORIA] ==0:
    return [PARCEL_SP]
  else:
    return  [NUM_CATASTRO]

The issue is that I can see labels for NUM_CATASTRO where they should, but none for PARCEL_SP. 

If I reverse the values...

def FindLabel (  [CATEGORIA],[NUM_CATASTRO], [PARCEL_SP] ):
  if [CATEGORIA] ==0:
    return  [NUM_CATASTRO]
  else:
    return [PARCEL_SP]

it labels the PARCEL_SP where is supposed to but not the NUM_CATASTRO.

Same thing using the following statement...

def FindLabel (  [CATEGORIA],[NUM_CATASTRO], [PARCEL_SP] ):
  if [CATEGORIA] !=0:
    return   [PARCEL_SP]
  else:
    return  [NUM_CATASTRO]

Any help will be appreciated...

Thanks

[TomSellsted]

Greeting Ulises!

It is most likely that the values in [CATEGORIA] are not what you are expecting them to be in python.  If the field is not numeric, it will never evaluate to 0, but a text value of  "0".  It may be a Null value and again it would not evaluate to be 0.  Your logic looks sound, please check the values and make sure it is the right field type.

Regards,

Tom

[Ulises]

Thanks for the reply, Tom.

Field CATEGORIA is numeric, yet I'm assuming is behaving like it isn't, yet haven't been able to identify why.

[TomSellsted]

Ulises,

Are there 0 values in the field [CATEGORIA] or could it be a value of null?

Regards,

Tom

[Ulises]

No null values...

[TomSellsted · Accepted solution]

Ulises,

It looks like python automatically casts numeric field values as strings, so you would need to change your expression to

if [CATEGORIA] == "0":

or

if int([CATEGORIA]) == 0:

[Ulises]

Thanks again.  Is not working either way.  First suggestion "0" still behaves as mentioned earlier and second option (using int) returned an error...

ValueError: invalid literal for int() with base 10:'N/A'

N/A is the descriptive value for the subtype coded with the integer 0.  Also changed the expression to evaluate against "N/A" with no success.

[TedKowal]

Your logic look good!

If you are sure that your Catagoria is numeric not null ect..... Then have tried another logical method such as :

def FindLabel (  [CATEGORIA],[NUM_CATASTRO], [PARCEL_SP] ):  
  if [CATEGORIA] > 0:  
    return [PARCEL_SP]  
  else:  
    return  [NUM_CATASTRO]

?

[Zeke]

I don't think python would be casting numeric data types to strings. That doesn't make sense.

[TomSellsted]

Greg,

That is straight from the "Building Label Expressions" in the ArcGIS Documentation.  I did a test on my data and it absolutely does cast the field values into strings.

Regards,

Tom