Python将多个变量初始化为同一个初始值

Python initialize multiple variables to the same initial value

提问by Rivadiz

I have gone through these questions,

我经历过这些问题，

1. Python assigning multiple variables to same value? list behavior
   concerned with tuples, I want just variables may be a string, integer or dictionary
2. More elegant way of declaring multiple variables at the same time
   The question has something I want to ask, but the accepted answer is much complex

1. Python将多个变量分配给相同的值？列出与元组有关的行为
   ，我只希望变量可以是字符串、整数或字典
2. 更优雅的同时声明多个变量的方法
   这个问题有我想问的，但接受的答案很复杂

so what I'm trying to achieve,

所以我正在努力实现的目标

I have this variables declared, and I want to reduce this declarations to as less line of code as possible.

我声明了这个变量，我想把这个声明减少到尽可能少的代码行。

details = None
product_base = None
product_identity = None
category_string = None
store_id = None
image_hash = None
image_link_mask = None
results = None
abort = False
data = {}

What is the simplest, easy to maintain ?

什么是最简单、易于维护的？

采纳答案by Shan

I agree with the other answers but would like to explain the important point here.

我同意其他答案，但想在这里解释重要的一点。

Noneobject is singleton object. How many times you assign None object to a variable, same object is used. So

None对象是单例对象。将 None 对象分配给变量多少次，使用了相同的对象。所以

x = None
y = None

is equal to

等于

x = y = None

but you should not do the same thing with any other object in python. For example,

但是你不应该对 python 中的任何其他对象做同样的事情。例如，

x = {}  # each time a dict object is created
y = {}

is not equal to

不等于

x = y = {}  # same dict object assigned to x ,y. We should not do this.

回答by DasFranck

details, producy_base, product_identity, category_string, store_id, image_hash, image_link_mask, results = None, None, None, None, None, None, None, None; abort = False; data = {}

details, producy_base, product_identity, category_string, store_id, image_hash, image_link_mask, results = None, None, None, None, None, None, None, None; abort = False; data = {}

That's how I do.

我就是这样做的。

回答by Aske Doerge

First of all I would advice you not to do this. It's unreadable and un-Pythonic. However you can reduce the number of lines with something like:

首先，我建议你不要这样做。它不可读且非 Pythonic。但是，您可以通过以下方式减少行数：

details, product_base, product_identity, category_string, store_id, image_hash, image_link_mask, results = [None] * 8
abort = False
data = {}

回答by jerblack

I have a one-line lambda function I use that helps me out with this.

我有一个单行 lambda 函数可以帮助我解决这个问题。

nones = lambda n: [None for _ in range(n)]
v, w, x, y, z = nones(5)

The lambda is the same thing as this.

lambda 与此相同。

def nones(n):
    return [None for _ in range(n)]

回答by Stan

This does not directly answer the question, but it is related -- I use an instance of an empty class to group similar attributes, so I do not have to clutter up my initmethod by listing them all.

这并没有直接回答问题，但它是相关的——我使用一个空类的实例来对相似的属性进行分组，所以我不必通过列出所有的init方法来弄乱我的init方法。

class Empty:
    pass

class Application(tk.Frame):
    def __init__(self, master=None):
        super().__init__(master)
        self.w = Empty()          # widgets
        self.master = master
        self.pack()
        self.create_widgets()

    def create_widgets(self):
        self.w.entry = tk.Entry(self, bg="orange", fg="black", font=FONT)

What is the difference between SimpleNamespace and empty class definition?

SimpleNamespace 和空类定义有什么区别？

回答by belgacea

A mix of previous answers :

先前答案的混合：

def default(value, number):
    return [value] * number

v, w, x, y, z = default(20, 5)