使用类属性访问字典 [英] Accessing dictionary with class attribute

问题描述

现在我正在使用python.所以有一个关于字典的问题.... 假设我有一个命令

now I am working with python. So one question about dict .... suppose I have a dict that

config = {'account_receivable': '4', 'account_payable': '5', 'account_cogs': '8', 'accoun
t_retained_earning': '9', 'account_income': '6', 'account_expense': '31', 'durat
ion': 2, 'financial_year_month': 9, 'financial_year_day': 15, 'account_cash': '3
', 'account_inventory': '2', 'account_accumulated_depriciation': '34', 'account_
depriciation_expense': '35', 'account_salary_expense': '30', 'account_payroll_pa
yable': '68', 'account_discount': '36', 'financial_year_close': '2008-08-08'}

如果打印-> config ['account_receivable']，它将返回其对应的值4

if print --> config['account_receivable'] it will return its corresponding value that 4

但是我想通过这种方式访问​​它-> config.account_receivable，然后它将返回对应的值

but I want to access it by that way--> config.account_receivable and then it will return it corresponding value

我该如何实现呢?

推荐答案

为此，很多年前，我发明了简单的Bunch习惯用语.实现Bunch的一种简单方法是:

For that purpose, lo that many years ago, I invented the simple Bunch idiom; one simple way to implement Bunch is:

class Bunch(object):
  def __init__(self, adict):
    self.__dict__.update(adict)

如果config是字典，则不能使用config.account_receivable，这是绝对不可能的，因为字典没有拥有该属性，句点.但是，您可以 将config包装到Bunch中:

If config is a dict, you can't use config.account_receivable -- that's absolutely impossible, because a dict doesn't have that attribute, period. However, you can wrap config into a Bunch:

cb = Bunch(config)

然后访问cb.config_account您内心的内容！

and then access cb.config_account to your heart's content!

编辑:如果您希望Bunch上的属性分配也影响原始的dict(在这种情况下为config)，例如cb.foo = 23将执行config['foo'] = 23，您需要一个完全不同的Bunch实现:

Edit: if you want attribute assignment on the Bunch to also affect the original dict (config in this case), so that e.g. cb.foo = 23 will do config['foo'] = 23, you need a slighly different implementation of Bunch:

class RwBunch(object):
  def __init__(self, adict):
    self.__dict__ = adict

通常，纯Bunch是首选，完全是，因为 在实例化之后，Bunch实例和从其启动"的dict会完全解耦-更改为它们中的一个不影响另一个；而这种去耦通常是我们所希望的.

Normally, the plain Bunch is preferred, exactly because, after instantiation, the Bunch instance and the dict it was "primed" from are entirely decoupled -- changes to either of them do not affect the other; and such decoupling, most often, is what's desired.

当您要做想要耦合"效果时，RwBunch是获取效果的方法:使用它，实例上的每个属性设置或删除都将固有地设置或删除该项目. dict，反之亦然，从dict设置或删除项目将本质上从实例设置或删除属性.

When you do want "coupling" effects, then RwBunch is the way to get them: with it, every attribute setting or deletion on the instance will intrinsically set or delete the item from the dict, and, vice versa, setting or deleting items from the dict will intrinsically set or delete attributes from the instance.

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