Let's say I create an instance of a class and want to assign some values to its public properties. Usually, this would be done like this:
class MyClass:
def __init__(self):
self.name = None
self.text = None
myclass = MyClass()
myclass.name = 'My name'
But, what if a write a function that takes a class as parameter and I would like to assign some values to the public properties of that class dynamically - that is via variables and loops (without knowing how many there are or what they are called.)
The obvious would be:
myclass = MyClass()
myclass['name'] = "My name"
But that doesn't work.
Any ideas?
setattr(my_class_instance, 'attr_name', attr_value)
After reading rejected Syntax For Dynamic Attribute Access I'm using a mixin class providing dictionary-style access to an object's attributes :
class MyClass:
def __init__(self):
self.name = None
self.text = None
def __getitem__(self, name):
return getattr(self, name)
def __setitem__(self, name, value):
return setattr(self, name, value)
def __delitem__(self, name):
return delattr(self, name)
def __contains__(self, name):
return hasattr(self, name)
While still being able to set attributes directly:
myclass = MyClass()
myclass.name = "foo"
myclass.text = "bar"
it's then possible to set them dynamically :
for attr in ('name', 'text'):
myclass[attr] = confirm(attr, default=myclass[attr])
Using dir with setattr should do the job
class MyClass:
def __init__(self):
self.name = None
self.text = None
myclass = MyClass()
myclass.name = 'My name'
for prop in dir(myclass):
print '%s:%s'%(prop,getattr(myclass,prop))
print
for prop in dir(myclass):
if prop[:2]!='__' and prop[-2:]!='__':
print prop[-2:]
setattr(myclass,prop,"Foo Bar")
for prop in dir(myclass):
print '%s:%s'%(prop,getattr(myclass,prop))
But be careful because this code also sets '__doc__', '__init__', '__module__' properties to "Foo Bar". So you will have to take care of avoiding certain things given to you by dir (especially those which start and end with __ double underscores).
