Programming ArcGIS 10.1 with Python Cookbook

Updating rows with an UpdateCursor

If you need to edit or delete rows from a table or feature class, you can use UpdateCursor. As is the case with InsertCursor, the contents of UpdateCursor can be limited through the use of a where clause.

Getting ready

The UpdateCursor() function can be used to either update or delete rows in a table or feature class. The returned cursor places a lock on the data, which will automatically be released if used inside a Python with statement. An UpdateCursor object is returned from a call to this method.

The UpdateCursor object places a lock on the data while it's being edited or deleted. If the cursor is used inside a Python with statement, the lock will automatically be freed after the data has been processed. ...