Basic If/Then in Python Parser of ArcGIS Field Calculator?

Question

I am using ArcGIS 10.2 for Desktop, and I've been looking through this site, and can't seem to figure out my answer yet. Very new to VBA and Python, but lots of years with ArcGIS. I know I can do this the slow way with Select By Attributes, but It's time consuming.

I am attempting a spatial join between cases of a disease (points layer) and US Census Tracts (polygon layer). This requires count data. For each point/case, I have a field called YEAR with date ranges 2001 to 2012 depending on what year the case happened. I need a count column for each year. For example, the first one I'm calling COUNT01. If the case date in YEAR is 2001, then COUNT01 will have a 1 in it. If it is any other year (2002-2012), then there will need to be a 0. I will have COUNT02, COUNT03...COUNT12 columns. Can't have a "Null" value.

Here's what I've tried so far

And here is what the data looks like in Arc.

Answer 1

I think this is what you want .... using python you could do the following (assumes YEAR and COUNT0X fields are integers)

• Change to Python as highlighted below
• Add the code to the 'Pre Logic' input box
• Change the yearVal as needed for each field you calculate (Count01 would use 2001, Count02 would use 2002, etc)

Note Python using indentation to parse the code so ensure the spacing is correct.

def myCalc(year,yearVal):
  if (year == yearVal):
    return 1
  else:
    return 0

Answer 2

This answer is essentially the same as listed above, however it's a way to not have to use the code block... for the Count01 field, you would set the parser to Python and then set your calculation to

1 if !YEAR! == 2001 else 0

The way this reads is: Set the field to 1 if the YEAR field is 2001, if it's not 2001, then set it to 0...

If you have multiple if conditions, you can nest the 2nd (and subsequent) "if" conditions inside the else statement, such as this...

1 if !YEAR! == 2001 else (2 if !YEAR! == 2002 else 0)

The way this reads is: Set the field to 1 if the YEAR field is 2001, if it's not 2001, then set it to 2 if it's 2002, if not, then set it to 0...

Answer 3

If you are going to use VBScript then your field calculation was set up wrong. Firstly I would not use a variable which is the name of the field, this is confusing, use a different name so its crystal clear what you were setting. Your "endif" was wrong it should be "end if" and your code should have been in the pre-logic script section. The correct way of setting this up is shown below. But as the others have said, try not to use VBScript as ESRI are hell bent on getting rid of it in favour of Python.