Python support for iterators of data; features, rows, field values

Idea created by dejames on May 9, 2013
         Using the MakeFeatureLayer and SearchCursor to create a list of features for acting on individual features in a feature class is cumbersome. 
    The current Listing methods arcpy only support classes of data (workspaces, feature classes, raster...).  These methods should be extended to include lists of the actual data (features, rows, field values).

    The following iteration methods, available only to ModelBuilder users, should have a complimentary method in arcpy for use in Python scripts.
    •           Iterate Feature Selection:  Iterates over features in a feature class.
    •           Iterate Row Selection:  Iterates over rows in a table.
    •           Iterate Field Values:  Iterates over each value in a field.
    •           Iterate Multivalue:  Iterates over a list of values.