# How to use Fields in the Field Calculator? [duplicate]

I'm using the Field Calculator in ArcMap and I need to create a unique ID for every storm drain in my county. An ID Should look something like this: 16-I-003

The first number is the municipal number which is in the column/field titled "Munic"

The letter is using the letter in the column/field titled "Point"

The last number is simply just 1 to however many drains there are in a municipality.

So far I have:

``````rec=0
def autoIncrement()
pStart=1
pInterval=1
if(rec==0):
rec=pStart
else:
rec=rec+pInterval
return "16-I-" '{0:03}'.format(rec)
``````

So you can see that I have manually been typing in the municipal number, the letter, and the hyphens. But I would like to pull the first number and letter from the fields: Munic and Point so I don't have to manually type them in each time it changes. I was hoping I could just put !Munic! and !Point! in my return statement before the .format(rec) or somehow work it in there.

I'm a beginner when it comes to python and ArcMap, so please dumb things down a little. The simpler the better!

## marked as duplicate by Paul, Chad Cooper, Jason Scheirer, Chris W, Mapperz♦Jun 26 '14 at 20:34

I am unclear about your function's logic, but I would approach it like this...

Expression:

``````autoIncrement(!Munic!, !Point!)
``````

Expression Type:

``````PYTHON_9.3
``````

Code Block:

``````rec = 0
def autoIncrement(munic, point)
pStart=1
pInterval=1
if(rec==0):
rec=pStart
else:
rec=rec+pInterval
return '{0}' "-" '{1}' "-" '{2:03}'.format(munic, point, rec)
``````