5

we need just like the following, only with multiple records selected... have tried the "xyz" in (1,2,3,4,5) SQL code but of course VB Script wants something else.

dim f2
if [field1] = "foo" then
  f2 = "bar"
end if

Screen shot of this being used in the field calculator.

enter image description here

4
  • 3
    I like the idea of being able to use custom code logic in the field calculator, might be something to add to QGIS.
    – Nathan W
    Mar 9, 2011 at 5:42
  • Hi Sirgeo, welcome to GIS.se :) For code formatting while editing select the relevant text and slap [ctrl]-[k]. Mar 9, 2011 at 18:49
  • 1
    Nathan, I downloaded QGIS yesterday and was very impressed with it. Looks like ESRI has some serious competition there, QGIS is a breath of fresh air in terms of user-friendliness and easy functionality. A custom code logic addition to QGIS's Field Calculator would make it perfect.
    – sirgeo
    Mar 10, 2011 at 17:19
  • the vb works well but I was trying to nest the if and it doesn't work. I tried adding if statements after the initial end if. Also I get a warning that field 1 is empty and have to click yes to continue...can this be stopped?
    – GeorgeC
    Oct 26, 2011 at 10:14

2 Answers 2

7

If you like SQL, you can apply a Definition Query:

IN('x','y','z')

then process your field calculator results. Only the filtered records will be modified.


If you want Python, it will look similar to the SQL:

if !field1! in ("x","y","z"):
    f2 = "field1 is yep"

[Added as solution] Or as a 1-liner without any preprocessing required:

'yes' if !field1! in ('x','y','z') else ''
9
  • Thanks for the reply Mike, i need to be able to do it all in one step (will have to do the same operation hundreds of times). Can you post the entire Python code for Pre-Logic? Or the VB Script equivalent using SQL's IN operator? Have tried it 20 different ways and it doesn't like the SQL is my guess. screen shot: i.imgur.com/GsBMs.jpg
    – sirgeo
    Mar 9, 2011 at 13:50
  • also, that screen shot doesn't have "then" or "end if" in it, but i fixed that i still get the same errors
    – sirgeo
    Mar 9, 2011 at 14:45
  • 3
    For Python, you could probably jump the whole pre-logic and use a one-liner: 'yes' if !field1! in ('x','y','z') else 'no'
    – Mike T
    Mar 9, 2011 at 23:53
  • Thanks Mike, i will give that a shot first thing tomorrow.... i do see there is no Then in your suggestion, not sure if it will work without a Then but will definitely try it.
    – sirgeo
    Mar 10, 2011 at 1:52
  • 1
    SOLUTION --- 'yes' if !sc2! in (14175,14161,14180,13459,13460,14652,14648,14647,14644) else '' simply take everything out of the '' after the else..... I have a new found love for Python, much thanks to all contributions here!
    – sirgeo
    Mar 10, 2011 at 14:05
3

It appears that you're trying to conditionally calculate the value of field 2 based on the value of field 1. you could do the entire operation in a python script using a combination of Mike's suggestion and an UpdateCursor something like this:

cursor = gp.UpdateCursor(yourfeatureclass)
row = cursor.Next()

while row:
     for row.GetValue("yoursourcefield") in ["foo", "bar", "snafu"]:
          row.YOURTARGETFIELD = "your target value"
     cursor.UpdateRow(row)
     row = cursor.Next()

otherwise, using just the pre-logic and the calculator, if it's just a boolean check, personally I'd do the inverse of what Mike suggested:

if [field1] not in ["x","y","z"]:
     [field2] = "NO WAY JOSE"
else:
     [field2] = "shoot'em up cowboy"
7
  • thanks Luke, i think i need to stay with VB Script on this one if possible.... i understand very little Python.... where does the "dim f2" and "f2" go into your VBScript example? sorry if this seems so simple, code is not my forte.
    – sirgeo
    Mar 9, 2011 at 17:33
  • You can look at it as the nice part about python, you don't have to make that verbose declarative statement. But you can replace [field2] with some variable name and input the new variable name in the bottom portion of the field calculator and get the same affect.
    – Luke
    Mar 9, 2011 at 18:01
  • can you do a screen of your field calculator with all this code in it? One of the confusing things is how Field Calculator labels any field double clicked with two "!!" around it.... why do the examples given here use brackets [] around the fields and not "!!" ?
    – sirgeo
    Mar 9, 2011 at 19:01
  • @sirgeo, the syntax changes depending on whether the data is shapefile, personal geodatabase, filegdb, etc. (see Arcgis 9.3 SQL Reference. Scroll down to "Comparison operators" to see example of the IN operator. Mar 9, 2011 at 19:29
  • Matt, doesn't that link only give syntax parameters for SQL? I need the VBScript equivalent for SQL's "STATE_NAME" IN ('14175','14161','14180') operation. This is a shape file i am trying to populate with a new identifier field. ArcGIS 10's field calculator only uses VBScript and Python yes?
    – sirgeo
    Mar 9, 2011 at 19:33

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