Getting a list of layers in a map document

Frequently, one of the first steps in a geoprocessing script is to obtain a list of layers in the map document. Once obtained, your script might then cycle through each of the layers and perform some type of processing. The mapping module contains a ListLayers() function that provides the capability of obtaining this list of layers. In this recipe, you will learn how to get a list of layers contained within a map document.

Getting ready

The arcpy.mapping module contains various list functions to return lists of layers, data frames, broken data sources, table views, and layout elements. These list functions are normally the first step in a multi-step process, where the script needs to get one or more items from a list for further processing. Each of these list functions returns a Python list, which as you know from earlier in the book, is a highly functional data structure for storing information.

Normally, the list functions are used as part of a...