Labeling features with ArcPy

Question

I had run the contour tool in my script to generate polylines.

Contour("rectExtract", "C:/fakepath/Class1.shp", 50,0)

Now I want to label the polylines with the contour-value. If I execute this script:

layer = arcpy.mapping.ListLayers(IMXD, "")[1]
layer.showLabels=True
arcpy.RefreshActiveView()

it will label the polylines with the ID-Value.

How can I change this?

Answer 1

If you have only one label class it's

layer.labelClasses[0].expression = "[<field expression here>]"
layer.showLabels = True
arcpy.RefreshActiveView()

Tested in ArcGIS 10.1