On 2019-06-23 10:44, Arup Rakshit wrote:
On 23-Jun-2019, at 2:31 PM, Cameron Simpson <c...@cskk.id.au> wrote:
On 23Jun2019 13:26, Arup Rakshit <a...@zeit.io> wrote:
In the below code:
@classmethod
def find(self, id):
if isinstance(id, list):
rows = self.__table__().get_all(*id).run(self.__db__().conn)
result = []
for row in rows:
acategory = Category()
acategory.__dict__.update(row)
result.append(acategory)
return result
else:
adict = self.__table__().get(id).run(self.__db__().conn)
acategory = Category()
acategory.__dict__.update(adict)
return acategory
I have 2 questions:
1. Is there any better way to create attributes in an object without using
__dict__().update() or this is a correct approach?
setattr() is the usual approach, but that sets a single attribute at a time. If
you have many then __dict__.update may be reasonable.
You should bear in mind that not all objects have a __dict__. It is uncommon,
but if a class is defined with a __slots__ attribute then its instances have
fixed attribute names and there is no __dict__. Also some builtin types have
not __dict__. However, you likely know that the objects you are using have a
__dict__, so you're probably good.
Also, __dict__ bypasses properties and descriptors. That might be important.
2. Can we get the same result what for row in rows: block is producing without
killing the readability ?
Not obviously. It looks pretty direct to me.
Unless the Category class can be made to accept an attribute map in its __int__
method, then you might do some variable on:
result = [ Category(row) for row in rows ]
which is pretty readable.
BTW, @classmethods receive the class as the first argument, not an instance. So
you'd normally write:
@classmethod
def find(cls, id):
…
What I know, is that first argument is reserved for the instance upon which it
is called. It can be any name, so continued to use self. Yes these methods are
class method intentionally. I am not aware of so far the naming rules of the
first argument of a class or instance method.
As Cameron wrote, the convention is that if it's an instance method you
call its first parameter "self", whereas if it's a class method you call
its first parameter "cls".
[snip]
--
https://mail.python.org/mailman/listinfo/python-list
