Replacing "_" with " " for classLabels using Python

[DerekNelson]

Head banging against a wall...

I have figured how to do this for layer name. The Help Docs say it is possible to change classLabel but don't show any examples and I can't find anyone who has successfully done this through Python. I am sure the answer lies in arcpy.mapping and UniqueValuesSymbology but cannot figure it. I have 10-15 different layers, all using unique_values for symbology, consisting of about 15-20 different classes in each. Each class value and therefore label uses an "_" instead of a space as is common practice for GIS data. For legend and TOC purposes, I am trying to figure a script that can quickly manipulate and change the classLabels in Layer Properties.

Any ideas would be wonderful...thanks!

[JoshuaBixby]

The following code from the interactive Python window in ArcMap should help get you going:

mxd = arcpy.mapping.MapDocument("CURRENT")
for lyr in arcpy.mapping.ListLayers(mxd):
    if lyr.symbologyType in ["GRADUATED_COLORS", "GRADUATED_SYMBOLS"]:
        print lyr.symbology.classBreakLabels
    elif lyr.symbologyType in ["UNIQUE_VALUES"]:
        print lyr.symbology.classLabels

The classBreakLabels and classLabels properties are read-writeable and store lists.  After you get the list, update the contents, and set the properties again; you will need to run arcpy.RefreshActiveView() to see the changes.

[DerekNelson]

Joshua,

So it did grab and create the list from the available classLabels. How do I then go about replacing the underscores with spaces though. You say "update the contents, and set the properties again", what does that mean? I am an admitted Python amateur and quite frankly still lost. This is where I'm at (couldn't figure out how to add script like you did to the discussion):

Again...thanks for any advice!

[JoshuaBixby · Accepted solution]

For inserting scripts, i.e., syntax highlighting, you need to use the advanced editor that is accessed from a link in the upper-right corner of the reply window/frame.

Try the following:

for lyr in arcpy.mapping.ListLayers(mxd):
    if lyr.symbologyType in ["GRADUATED_COLORS", "GRADUATED_SYMBOLS"]:
        labels = lyr.symbology.classBreakLabels
        for i, label in enumerate(labels):
            labels = label.replace("_", " ")
        lyr.symbology.classBreakLabels = labels
    elif lyr.symbologyType in ["UNIQUE_VALUES"]:
        labels = lyr.symbology.classLabels
        for i, label in enumerate(labels):
            labels = label.replace("_", " ")
        lyr.symbology.classLabels = labels

• Since the class labels are properties and return a list, you need to "get" the lists, which is what I am doing in lines 03 and 08.
• Since the labels are stored in a list, you need to iterate over the list and do the text replace/substitution on each element of the list.  Lines 04-05 and 09-10.
  • There are several ways to handle this part.  One could create a new list, using a for loop or list comprehension  I chose to edit the existing list in place, using a for loop and an enumerate object.
• After the label updates are done, you need to "set" the properties to the new or updated lists, which is what I am doing in lines 06 and 11.

[DerekNelson]

Joshua,

You are the MAN! Had to substitute some single quotes for the doubles you had in the replace areas, added it to my script for renaming the layers with a "arcpy.RefreshTOC()" and presto! Thanks so much for the help!

[JoshuaBixby]

Your welcome.  Keeping plugging away at learning Python, I know I have really enjoyed learning and applying it, there is so much you can do with it.  Cheers....