Using Field Calculator with Python Parser and if/elif statements in ArcGIS for Desktop?

Question

I have tried all of below snippets to use Python Parser in Field Calculator and update the values of a field called type based on a filed called MamerMN but in all of them I am getting Syntax error in Geoprocessing result window!

if !MamerMN! <= 0.151560:
    return 1

and

if (!MamerMN! <= 0.151560):
    return 1

and

if (MamerMN <= 0.151560):
    return 1

and

def(MamerMN)
if MamerMN <= 0.151560:
    return 1

and

def(MamerMN)
if (MamerMN <= 0.151560):
    return 1

Can you please let me know what I am doing wrong?

Update

def foo(MamerMN):
  if MamerMN <= 0.151560:
     return 1

Are you placing this in the codeblock? You need to make sure you're using proper indentation as well. The last two are not proper python syntax either. it should be def foo(bar): return bar**bar — Paul, Aug 18 '15 at 20:00
@Paul , can you please let me know what do you mean by codeblock? — Suffii, Aug 18 '15 at 20:01
@Paul, Can you please take a look at Update code? I am using exactly what you have said and based on the example but st getting error! — Suffii, Aug 18 '15 at 20:07
Ok, so if that is your code block then the expression should look like foo(!MamerMN!) — Paul, Aug 18 '15 at 20:14
There are many earlier duplicates for this one, another is http://gis.stackexchange.com/questions/99615/writing-conditional-if-then-statements-into-field-calculator-of-arcgis-for-des — PolyGeo, Aug 18 '15 at 23:03

score 2 · Answer 1 · edited Apr 13 '17 at 12:33

Thanks to Paul

Here is the solution: in Pre-logic Script Code Box:

def foo(MamerMN): 
  if (MamerMN <= 0.200000): 
     return 1
  elif (MamerMN >= 0.200001 and  MamerMN <= 0.400000):
     return 2
  elif (MamerMN >= 0.400001 and  MamerMN <= 0.600000):
     return 3
  elif (MamerMN >= 0.600001 and  MamerMN <= 0.800000):
     return 4
  elif (MamerMN >= 0.800001):
     return 5

and in Expression box

foo( !MamerMN! )

Using Field Calculator with Python Parser and if/elif statements in ArcGIS for Desktop?

1 Answers1