Quickly formats the names of all the layers in a map document.

reformatAllLayerNames.py

#
# @date 14/08/2015
# @author Cindy Williams
#
# Quickly formats the names of all the layers in a map
# document. In this example, the part of the name before
# the first full stop is removed, underscores are replaced
# spaces, a regex is used to insert spaces before capitals
# and the string is converted to proper case.
#
# For use in the Python window in ArcMap.
#

import arcpy
import re

mxd = arcpy.mapping.MapDocument("CURRENT")
lyrs = arcpy.mapping.ListLayers(mxd)

for lyr in lyrs:
  new_name_replaced = lyr.name.split(".")[1].replace("_", " ")
  new_name_spaced = re.sub(r"(\w)([A-Z])", r"\1 \2", new_name_replaced)
  lyr.name = new_name_spaced.title()
  
arcpy.RefreshTOC()