不使用 def __init__(self) 的 Python 类
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Python Classes without using def __init__(self)
提问by dman
I am writing a series of text menus. With the class and sub class below it runs with no issues. But I am reviewing my coding and I am wondering....is it ok that I didn't use def __init__(self)in the classes? Should I have placed the data members in def __init__(Self):such as self.images = (), self.options =()? If I did that then I could not use the abc module for restrains, correct?
我正在编写一系列文本菜单。使用下面的类和子类，它运行没有问题。但我正在检查我的编码，我想知道......我没有def __init__(self)在课堂上使用可以吗？我应该将数据成员放在def __init__(Self):诸如 self.images = (), self.options =() 之类的地方吗？如果我这样做了，那么我就不能使用 abc 模块进行限制，对吗？
class BaseMenu(object):
__metaclass__ = abc.ABCMeta
@abc.abstractproperty
def options(self):
pass
@abc.abstractproperty
def menu_name(self):
pass
def display(self):
header = "FooBar YO"
term = getTerminalSize()
#sys.stdout.write("\x1b[2J\x1b[H")
print header.center(term, '*')
print self.menu_name.center(term, '+')
print "Please choose which option:"
for i in self.options:
print(
str(self.options.index(i)+1) + ") "
+ i.__name__
)
value = int(raw_input("Please Choose: ")) - 1
self.options[value](self)
class Servers(BaseMenu):
menu_name = "Servers"
images = ()
foo = ()
def get_images(self):
if not self.images:
self.images = list_images.get_images()
for img in self.images:
print (
str(self.images.index(img)+1) + ") "
+ "Name: %s\n ID: %s" %
(img.name, img.id)
)
def get_foo(self):
if not self.foo:
self.foo = list_list.get_list()
for list in self.foo:
print "Name:", list.name
print " ID:", list.id
print
def create_servers(self):
create_server.create(self)
options = (
get_images,
get_foo,
create_servers
)
采纳答案by Martijn Pieters
Your code is perfectly fine. You don't haveto have an __init__method.
你的代码非常好。你不具备有一个__init__方法。
You can still use __init__, even with an ABC. All that the ABC meta tests for is if the nameshave been defined. Setting imagesin an __init__does requires that you define a class attribute, but you can set that to Noneat first:
__init__即使使用 ABC，您仍然可以使用。ABC 元测试的所有内容是名称是否已定义。images在do中设置__init__需要您定义一个类属性，但您可以首先将其设置为None：
class Servers(BaseMenu):
menu_name = "Servers"
images = None
foo = None
def __init__(self):
self.images = list_images.get_images()
self.foo = list_list.get_list()
Now you can set constraints on the ABC requiring that a imagesabstract property be available; the images = Noneclass attribute will satisfy that constraint.
现在您可以在 ABC 上设置约束，要求images抽象属性可用；在images = None类属性将满足该约束。
回答by Chandan
class A:
def a(self, a):
print(a)
ob = A()
ob.a("Hello World")
