Hi, Up to Python 2.2, type() was just a function to return an object type. >From 2.2 on, type have this behavior when called with only one argument and is used to create a new type when called with 3 arguments.
>From http://www.python.org/2.2/descrintro.html : "The signature of type() requires an explanation: traditionally, type(x) returns the type of object x, and this usage is still supported. However, type(name, bases, methods) is a new usage that creates a brand new type object. (This gets into metaclass programming, and I won't go into this further here except to note that this signature is the same as that used by the Don Beaudry hook of metaclass fame.)" So, an example: Foo = type('Foo', (object,), {}) and... class Foo(object): pass Are the same thing... On 30 Jan 2005 11:57:23 -0800 [EMAIL PROTECTED] wrote: > I was looking at Simon Burton's Povray.py code (part of pypov) and saw > this line: > globals()[name] = type( name, (KWItem,), {} ) # nifty :) > > where 'KWItem' was a class. It did seem nifty, but it was unclear to > me what was happening. > > I went to python.org's online documentation which said that type() > takes one argument. So I fired up python: > >>> type(42) > <type 'int'> > >>> type("x", (type(42),), {}) > <class '__main__.x'> > > OK, It appears that type() with 3 arguments constructs a class. Is > this documented somewhere? If not can someone explain what is going > on? james > > -- > http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
