I am a Python noob.
I create a class as follows:
class t1:
x = ''
def __init__(self, x):
self.x = x
class t2:
y = ''
z = ''
def __init__(self, x, y, z):
self.y = t1.__init__(x)
self.z = z
Now contrary to C++ or Java, I do not bind the data type to y while writing the class definition. It is only because the constructor code is such that it shows that y is of type t1. Can we bind a data type while declaring y?
No. Variables in Python do not have types - y does not have a type. At any moment in time, y refers to an object, and that object has a type. This:
y = ''
binds y to an object of type str. You can change it later to refer to an object of a different type. y itself has no intrinsic type.
See Fredrik Lundh's excellent "Reset your brain" article for further explanation.
(By the way, this: self.y = t1.__init__(x) is a rather strange piece of code. Did you mean to say self.y = t1(x)?)
str you mean.It's out of the scope, but please note:
class A(object):
x = None
In this context, x is a class variable, not an instance variable and is shared by each instance. It's commonly used in the borg pattern.
class A(object):
def __init__(self, x):
self.y = None
self.x = x
Here, self.y and self.x are instance variables.
