Lately I started looking into Django code and wish to write about internals of Django. I started with Django models and will be writing about it soon.
For understanding how Django models work, I had to understand what metaclasses are and how metaclasses work.
Metaclasses use method "__new__" and so I looked at what "__new__" does.
As __new__ is a static method, we will see a lttle bit about static methods and then __new__ in detail.
1. Understanding static methods.
2. Understanding method "__new__" of any class. We will see how to override method __new__ in a class.
Also, I will be trying all the code we write here on Ipython and I suggest you to try everything on Ipython as well.
Static methods
A little bit about instance methods first. Let's write a class.
...: def met(self, a, b):
...: print a, b
...:In this case, met() is an instance method. So, it is expected that we pass an instance of A as the first argument to met.
Let's create an object and call met() on the created object and pass two arguments to met().
In [5]: obj.met(1,2)
1 2 #output
For understanding how Django models work, I had to understand what metaclasses are and how metaclasses work.
Metaclasses use method "__new__" and so I looked at what "__new__" does.
As __new__ is a static method, we will see a lttle bit about static methods and then __new__ in detail.
1. Understanding static methods.
2. Understanding method "__new__" of any class. We will see how to override method __new__ in a class.
Also, I will be trying all the code we write here on Ipython and I suggest you to try everything on Ipython as well.
Static methods
A little bit about instance methods first. Let's write a class.
CODE:
In [1]: class A(object):...: def met(self, a, b):
...: print a, b
...:In this case, met() is an instance method. So, it is expected that we pass an instance of A as the first argument to met.
Let's create an object and call met() on the created object and pass two arguments to met().
CODE:
In [4]: bj = A()In [5]: obj.met(1,2)
1 2 #output
来自 “ ITPUB博客 ” ，链接：https://blog.itpub.net/301743/viewspace-732625/ ，如需转载，请注明出处，否则将追究法律责任。
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