Can you create a class from a string name

[Alex Martelli]

Vivek Sawant wrote:

> is there a way to create a class object or an instance object for a
> class if you have the name of the class as a string at the runtime.
> 
> For example, in Java you can create a 'Class' object as:
> 
> Class.forname ('<classname>')

In Python, what you load are *modules*, and classes (as well as
everything else) live in modules.  This is somewhat different from the
Java approach where classes are "directly loaded".

So, to "load and access" a class from a name, in Python you need
two steps, and two names:

-- a module name, which you will use to load the module (or to
   access it if it's already loaded);
-- a class name within the module.

def forname(modname, classname):
    module = __import__(modname)
    classobj = getattr(module, classname)
    return classobj

Note that, while I've used "classname" and "classobj" here, this is
NOT at all limited to classes -- it will access just as well any module
attribute at all, be it a class, a function, a number, whatever.

In practice one might be less didactic and more concise and generic:

def forname(modname, attname):
    return getattr(__import__(modname), attname)


Alex