topic Re: How can i change the layer label in TOC with py ? in Python Questions

How can i change the layer label in TOC with py ?

Raphael_Augusto_FoscariniFerre — Fri, 10 Dec 2021 20:19:10 GMT

I want to change this information, with python:

I have this code (got here: https://community.esri.com/thread/43148 ) , but it changes the layer name. I want to change layer label.

It is a simple feature, with no unique values.

import arcpy, os
from arcpy import env  
env.workspace = os.curdir

  
for mxdFile in arcpy.ListFiles("*.mxd"):  
    mxdPath = env.workspace + "\\" + mxdFile  
    mxd = arcpy.mapping.MapDocument(mxdPath)    
    layers = arcpy.mapping.ListLayers(mxd)    
        
    for lyr in layers:    
        if lyr.name == "old name":
            lyr.name = "newname"

    arcpy.RefreshTOC()
    mxd.save()‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: How can i change the layer label in TOC with py ?

IanMurray — Wed, 15 Mar 2017 19:43:10 GMT

I'm fairly certain that a layer label value is not exposed with the arcpy module and therefore cannot be changed with arcpy.

Re: How can i change the layer label in TOC with py ?

RebeccaStrauch__GISP — Wed, 15 Mar 2017 19:45:06 GMT

I wonder if you can use UniqueValuesSymbology—Help | ArcGIS for Desktop but "trick" the unique value to only have one. then use one of these properties?

I didn't see a set of properties for no-unique-values otherwise.

Re: How can i change the layer label in TOC with py ?

Raphael_Augusto_FoscariniFerre — Wed, 15 Mar 2017 19:49:58 GMT

The problem is, i need to change it in several mxds. More than 1000... And it would make changes in the legend in layout also, because would add 'headings', for example...

Thats why i want to try this way!! but thanks for the help...

Re: How can i change the layer label in TOC with py ?

IanMurray — Wed, 15 Mar 2017 19:54:55 GMT

Sheesh I'm slipping.... I remember looking at that about a month ago and reminding myself to use that if needed sometime.

Re: How can i change the layer label in TOC with py ?

Raphael_Augusto_FoscariniFerre — Wed, 15 Mar 2017 19:57:56 GMT

Please, try to remember it!!! i really need to change this automatically!!!

help me!

Re: How can i change the layer label in TOC with py ?

IanMurray — Wed, 15 Mar 2017 19:59:05 GMT

I doubt it would change your legend unless your legend item for that layer was already using a style item that used the layer heading. You could always change your legend item style to use only the layer name, or layer name and label only if you didn't want an heading added to them.

Re: How can i change the layer label in TOC with py ?

Raphael_Augusto_FoscariniFerre — Fri, 10 Dec 2021 20:19:13 GMT

I figured how to do it. I just need to change it, the way i want one time, than save a .lyr from the correct information (it can also change symbology, and other stuff).

The script below, will apply the .lyr file to your layer in the TOC. You just must specify the name of the layer, like displayed in TOC.

It will do to all MXD files, in the same folder of the script.

import arcpy, os
from arcpy import env  
env.workspace = os.curdir

  
for mxdFile in arcpy.ListFiles("*.mxd"):  
    mxdPath = env.workspace + "\\" + mxdFile  
    mxd = arcpy.mapping.MapDocument(mxdPath)    
    layers = arcpy.mapping.ListLayers(mxd)    
        
    for lyr in layers:    
        if lyr.name == "layer_name_in_TOC": #change here
            print mxdPath
            symbologyLayer = r"D:\LayerFile.lyr" #change here
            arcpy.ApplySymbologyFromLayer_management (lyr, symbologyLayer) 

            arcpy.RefreshTOC()
            mxd.save()‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: How can i change the layer label in TOC with py ?

JoshuaBixby — Thu, 16 Mar 2017 16:05:37 GMT

From your screenshot, it appears you are using ArcMap. If you are using ArcGIS Pro, there is a SimpleRenderer class you can use to simply and straightforwardly change a symbol layer for simple symbology.

Re: How can i change the layer label in TOC with py ?

WilliamKalande — Tue, 03 Jul 2018 08:33:02 GMT

Hi Ian, Here a year later. Can I edit labels so that I allocate a field in a layer manually or through arcpy? It is denoted as read/write but cant edit it other than through TOC.

Re: How can i change the layer label in TOC with py ?

JoshuaBixby — Fri, 10 Dec 2021 20:19:15 GMT

What version of ArcMap are you using? What is your current code and result?

I have ArcMap 10.6, and I can change the label class to point to a different field and it works fine:

>>> mxd = arcpy.mapping.MapDocument("CURRENT")
>>> lyr = arcpy.mapping.ListLayers(mxd)[0]
>>> lbl = lyr.labelClasses[0]
>>> lbl.expression = '[NEW_FIELD]'
>>> arcpy.RefreshActiveView()
>>> ‍‍‍‍‍‍

Re: How can i change the layer label in TOC with py ?

WilliamKalande — Wed, 04 Jul 2018 02:07:11 GMT

Thanks Joshua

I applied the code, it changes the expression label field as below and that is fine

What I need though is the TOC to maintain the value field assigned under symbology properties but allow me to use another field in the layer as a label or to copy the corresponding values into TOC. What I mean I want for instance the values below in the OpCodeBoundaries. The value field set in symbology is say field A. I want to maintain that but change the display in the TOC window to display values in Field B. Effectively, that will change the display in the legend

Re: How can i change the layer label in TOC with py ?

JoshuaBixby — Wed, 04 Jul 2018 14:29:37 GMT

Honestly, I am not certain what you are after. It seems like you are mixing symbology and labeling. Labels are displayed on the map, not in the TOC or a map legend. You can symbolize and label based on the same field/values; but if I understand what you are trying to do, it isn't possible, at least through ArcPy. That said, I might not understand what you are trying to accomplish.

Re: How can i change the layer label in TOC with py ?

WilliamKalande — Thu, 05 Jul 2018 01:03:40 GMT

You got me right Joshua. I want to allocate a field to a layer's label in symbology. That effectively changes the layer labels displayed in TOC. Not sure if it is possible. If it is it will save me a lot of time.

Alternatively, I can resolve the issue by finding a way to write into the TOC or copy field attributes into the TOC. Currently, I am copying and pasting a single field attribute at a time

Re: How can i change the layer label in TOC with py ?

JoshuaBixby — Thu, 05 Jul 2018 15:55:08 GMT

For ArcMap and ArcPy, definitely not possible. Beyond ArcMap, I still need to think about it.