Auto populate field with text using field calculator if/then

Question

I've extracted values from a raster to a point file, but now I need a field with the text information from the raster attribute table that corresponds with the value. I've been trying to use the field calculator to do an if/then type function, but I can't get it to work; Basically, where it says 1201 in the RASTERVALU field I want it to say "Developed, Open Space" in the CN_LEVEL3 Field. I have absolutely no experience with Python.

Answer 1

In your field calculator, select Python as your parser. In your code block:

def calcVal (inVal):
 if inVal == 1201:
   return "Developed, Open Space"

Then in your field calculation box:

calcVal(!RASTERVALU!)

Tweak as needed. Look into if/elif/else statements for a bit more complex logics.

Answer 2

To expand on the other answers:

If you will be defining other values from RASTERVALU, besides the 1201, to CN_LEVEL3 you can put a dictionary into the codeblock. Example (I made some random values):

def calcVal(inVal):
    values = {1201: "Developed, Open Space",
              1202: "Forest",
              1203: "Water"}
    if inVal in values.keys():
        return values[inVal]
    else:
        pass

Resources:

Python dictionary

Field calculator examples; 10.2

Answer 3

For a quick solution instead of using an if/than you could do a select by attribute then calculate the field on the selected records like this:

This is a quick approach if you only have to run this for one value however gm70560's answer is far superior if this has to be repeated for multiple values.

Answer 4

To avoid the need to use Python you can use Select By Attribute first. This is available as a tool, from the Selection pulldown or from Table Options. Then use Field Calculator or the Calculate Field tool to update just those features with the desired value.