topic Re: Problem with simple definition query expression in Python Questions

Problem with simple definition query expression

KONPETROV — Sat, 11 Dec 2021 19:45:55 GMT

I am trying to assign a value to two shapefiles in the first data frame of my .mxd with definition query, but it seems that cannot be done.

Any suggestion? Thanks

Here is the code:

import arcpy
mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]
for lyr in arcpy.mapping.ListLayers(mxd):  
    if lyr.name == "waste":  
        lyr.definitionQuery == "Code = 'IT1300021'"‍‍‍‍‍‍

Re: Problem with simple definition query expression

DanPatterson_Retired — Fri, 28 Apr 2017 10:39:14 GMT

what is the error or what is the result?

lyr.definitionQuery == .... this is an equality check not an assignment, which is what I think you want

Re: Problem with simple definition query expression

KONPETROV — Fri, 28 Apr 2017 11:03:10 GMT

good note, but is not working either with that. I get an error Runtime error SyntaxError: can't assign to comparison (<string>, line 6)

Re: Problem with simple definition query expression

DanPatterson_Retired — Fri, 28 Apr 2017 11:11:14 GMT

So no error? just nothing is happening?

It might be time to add

if lyr.supports("DEFINITIONQUERY"):

to the test to ensure your layers support a query and a couple of print statement to monitor progress, otherwise a malformed query should have at least thrown an error.

Re: Problem with simple definition query expression

KONPETROV — Sat, 11 Dec 2021 19:45:58 GMT

I ve also tried this, but didn't work also

import arcpy
mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]
aa = "'IT1300021'"
for lyr in arcpy.mapping.ListLayers(mxd):  
    if lyr.name == "waste":  
        lyr.definitionQuery == "'Code = {}'".format(aa)‍‍‍‍‍‍‍

Re: Problem with simple definition query expression

KONPETROV — Sat, 11 Dec 2021 19:46:01 GMT

I wrote that but...

import arcpy
mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]
aa = "'IT1300021'"
for lyr in arcpy.mapping.ListLayers(mxd):
   if lyr.supports("DEFINITIONQUERY"):
       if lyr.name == "waste":  
           lyr.definitionQuery == "Code = 'IT1300021'"‍‍‍‍‍‍‍‍

Re: Problem with simple definition query expression

DanPatterson_Retired — Fri, 28 Apr 2017 11:39:38 GMT

well lacking print statements, it isn't possible to see the code even gets into the sections where the definitions are being set. I can only refer you to the help topic where it states that the source and type of the layer is important, case sensitivity applies to one type and not another and that changes are not automatic but an update may need to be made. Hence, my recommendation about print statements to see what is going on....it is probably something obvious

http://desktop.arcgis.com/en/arcmap/latest/analyze/arcpy-mapping/updatingandfixingdatasources.htm

http://desktop.arcgis.com/en/arcmap/latest/analyze/arcpy-mapping/layer-class.htm

Re: Problem with simple definition query expression

JoshuaBixby — Fri, 28 Apr 2017 13:28:49 GMT

In both of your follow-up code snippets, you are still using an equality check (==) instead of an assignment (=). Even if all of the lines up to the final line worked, the final line of code isn't' going to update anything, it is only going to return a True or False that has no impact on anything.

Re: Problem with simple definition query expression

MitchHolley1 — Sat, 11 Dec 2021 19:46:04 GMT

Like Dan said, you should use = instead of ==.

import arcpy
mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]
for lyr in arcpy.mapping.ListLayers(mxd):  
    if lyr.name == "waste":  
        lyr.definitionQuery = "Code = 'IT1300021'"

arcpy.RefreshActiveView()‍‍‍‍‍‍‍‍

Re: Problem with simple definition query expression

MitchHolley1 — Tue, 09 May 2017 20:36:11 GMT

What's the status of this issue?

Re: Problem with simple definition query expression

DanPatterson_Retired — Sun, 21 May 2017 01:31:34 GMT

abandoned likely... converting to discussion