Apply Symbology from Layer Not Working in Script

Question

I am working on applying symbology to multiple layers from lyr files for multiple MXDs within the IDE. I have been able to access the MXDs and iterate through and change the definition of "mxd". I am receiving the following error, however, when the ApplySymbologyFromLayer_management process is run:

ERROR 000732: Input Layer: Dataset FCname does not exist or is not supported

My script is as follows:

# the MXDs to change, accessed and processed individually as 'i' is script not shown
mxd = arcpy.mapping.MapDocument(r'C:\Path\to\mxd\doc.mxd')
for lyr in arcpy.mapping.ListLayers(mxd):
    if lyr.name == 'FCname':
        arcpy.ApplySymbologyFromLayer_management(
            in_layer="FCname",
            in_symbology_layer="C:\Path\to\lyrs\FCname.lyr")

I have repeated the same ApplySymbologyFromLayer_management tool within ArcMap successfully. Any ideas on why this process is not succeeding within my script?

Answer 1

You want to execute your code in Standalone.So you can't use input layer name, just use layer without any properties like name,... . save your mxd after the symbology changes. You can save the current mxd or save to another mxd file (Save a Copy).

# the MXDs to change, accessed and processed individually as 'i' is script not shown
import arcpy
mxd = arcpy.mapping.MapDocument(r'C:\Path\to\mxd\doc.mxd')
for lyr in arcpy.mapping.ListLayers(mxd,"FCname"):
        arcpy.ApplySymbologyFromLayer_management(lyr,r"C:\Path\to\lyrs\FCname.lyr")
        mxd.saveACopy("C:/MychangeSymbology.mxd")