I'm new in programming so please don't kill me for asking stupid questions. I've been trying to understand all that class business in Python and I got to the point where could not find answer for my question just by google it.
In my program I need to call a class from within other class based on string returned by function. I found two solutions: one by using getattr() and second one by using globals() / locals().
Decided to go for second solution and got it working but I'm really don't understand how it's working.
So there is the code example:
class Test(object):
def __init__(self):
print "WORKS!"
room = globals()['Test']
room()
type(room()) gives:
<class '__main__.Test'>
type(room) gives:
<type 'type'> # What????
It looks like room() is a class object, but shouldn't that be room instead of room()?
Please help me because it is a little bit silly if I write a code which I don't understand myself.
What happens here is the following:
class Test(object):
def __init__(self):
print "WORKS!"
room = globals()['Test']
Here you got Test as room the way you wanted. Verify this:
room is Test
should give True.
type(room())gives:<class '__main__.Test'>
You do one step an go it backwards: room() returns the same as Test() would - an instance of that class. type() "undoes" this step resp. gets the type of the object - this is, of course, Test.
type(room)gives:<type 'type'> # What????
Of course - it is the type of a (new style) class. The same as type(Test).
Be aware, however, that for
In my program I need to call a class from within other class based on string returned by function. I found two solutions: one by using
getattr()and second one by usingglobals()/locals().
it could be better to create an explicitly separate dict. Here you have full control over which objects/classes/... are allowed in that context and which are not.