Python - Access object attributes as in a dictionary

getattr(my_object, my_str)

Or, if you're not sure if the name exists as a key and want to provide a fallback instead of throwing an exception:

getattr(my_object, my_str, "Could not find anything")

More on getattr.

You can provide support for the [] operator for objects of your class by defining a small family of methods - getitem and setitem, principally. See the next few entries in the docs for some others to implement, for full support.