finding name of instances created

[Georg Brandl]

Michael Tobis wrote:
> I have a similar problem. Here's what I do:
> 
> .def new_robot_named(name,indict=globals()):
> .   execstr = name + " = robot('" + name + "')"
> .   exec(execstr,indict)
> 
> .class robot(object):
> .   def __init__(self,name):
> .      self.name = name
> 
> .   def sayhi(self):
> .      print "Hi!  I'm %s!" % self.name
> 
> .if __name__=="__main__":
> .   new_robot_named('Bert')
> .   new_robot_named('Ernie')
> .   Ernie.sayhi()
> .   Bert.sayhi()

Uh. Try explaining this to newbies... ;)

On a second thought, the idea is quite usable considering some differences:

class Robot(object):
    # as above

class Robots(dict):
    def new(self, name):
        new_robot = Robot(name)
        self[name] = new_robot
        return new_robot
    def __getattr__(self, name):
        if name in self:
            return self[name]
        raise AttributeError

robots = Robots()
robots.new('Bert')
robots.new('Ernie')
robots.Bert.sayhi()
robots["Bert"].sayhi()

for robot in robots:
    robot.sayhi()

... etc ...

This doesn't include ugly globals() and exec "tricks".

Georg