Django - 可以迭代方法吗？ [英] Django - is it possible to iterate over methods?

问题描述

编辑： $ b $我正在Django的Web应用程序上工作，该应用程序适用于产品，价格和统计信息等。 b更明显的解释：如何组合或标记一些实例方法，以便我可以在中迭代它们，例如instance.name_of_the_group中的方法

为了保持简单 - 我有一个模型产品。 产品具有多种属性和方法。其中一些方法返回统计数据。

  class Product（models.Model）：
 name = 
 ... 
 
 def save（... 
 ... 
 
 def get_all_colors（self）：
 ... 
 
 def get_historical_average_price（self）：#statistic method 
 price =< some calculate> 
 return price 
 
 def get_historical_minimal_price（self）：＃统计方法
 ... 
返回价格
  

所以有很多方法如 get_historical_average_price 和 get_historical_minimal_price 。

现在我有编写标签并在项目中逐个调用这些方法，例如生成表或创建XML导出时。

我想要能够以某种方式标记他们那些是统计的方法，给他们一些名字，所以我可以使用为循环e tc。

有没有办法做到这一点？

XML生成器示例：

 < products> 
 {％for product in products％} 
< product> 
< code> {{product.code}}< / code> 
< name> {{product.name}}< / name> 
< statistics> 
< history_average> {{product.get_historical_average_price}}< / history_average> 
< minimal_price> {{product.get_historical_minimal_price}}< / minimal_price> 
< / statistics> 
< / product> 
 {％endfor％} 
< / products> 
  

所以我会这样做：

 <统计> 
 {％for product.statistics％}中的statistic_method 
 {{statistic_method.name}}> {{statistic_method}}< / {{statistic_method.name}}> 
 {％endfor％} 
< / statistics> 
  

而不是：

 <统计> 
< history_average> {{product.get_historical_average_price}}< / history_average> 
< minimal_price> {{product.get_historical_minimal_price}}< / minimal_price> 
< / statistics> 
  

解决方案

这是使用自定义模型管理器，您可以使用或覆盖他们在那里使用的名称。

所以在你的例子中，例如：

  class StatisticsManager model.Manager）：
 def history_average_price（self）：
 ... 
 
 class产品（models.Model）：
 name = ... 
 statistics = StatisticsManager（）
  

然后以 b

product_price = Product.statistics.get_historical_average_price

等等。

编辑：

我忘了 - 当你覆盖默认的 / code>经理，我相信您需要根据这篇文章 - 但是如果需要，你可以在对象上有多个管理员，所以对象， statistics ， otherstuffhere 。

I'm working on a Web Application in Django which works with products, prices and statistics etc.

EDIT: More straighforward explanation: How to "group" or "mark" some of instance methods so I can iterate over them like for method in instance.name_of_the_group

To keep it simple - I have a model Product. Product has multiple attributes and methods. Some of those methods returns "statistics" data.

class Product(models.Model):
    name = ...
    ... 

    def save(...
    ...

    def get_all_colors(self):
    ....

    def get_historical_average_price(self): #statistic method
        price = <some calculation>
        return price

    def get_historical_minimal_price(self): #statistic method
        ...
        return price

So there is a lot of methods like get_historical_average_price and get_historical_minimal_price.

Now I have to write labels and call these methods one by one in the project. For example when I generate a table or creating an XML export.

I would like to be able to somehow "mark" them that those are "statistic" methods, give them some name so I would be able to work with them using for loops etc.

Is there some way to do that?

Example on XML generator:

<products>
    {% for product in products %}
        <product>
            <code>{{ product.code }}</code>
            <name>{{ product.name }}</name>
            <statistics>
                <historical_average>{{ product.get_historical_average_price}}</historical_average>
                <minimal_price>{{ product.get_historical_minimal_price}}</minimal_price>
            </statistics>
        </product>
    {% endfor %}
</products>

So I would do something like:

<statistics>
{% for statistic_method in product.statistics %}
    <{{ statistic_method.name }}>{{ statistic_method }}</{{ statistic_method.name }}>
{% endfor %}
</statistics>

instead of:

<statistics>
     <historical_average>{{ product.get_historical_average_price}}</historical_average>
     <minimal_price>{{ product.get_historical_minimal_price}}</minimal_price>
</statistics>

解决方案

This is a great use case for using custom model managers as you can use or override the names that they use there.

So in your example, something like :

class StatisticsManager(models.Manager):
    def historical_average_price(self):
        ...

class Product(models.Model):
    name = ... 
    statistics = StatisticsManager()

Which would then be called in the form

product_price = Product.statistics.get_historical_average_price

and so on.

Edit:

I forgot - as you're overriding the default objects manager, I believe that you'll need to explicitly restate that as a manager, per this article - but you can have multiple managers on an object if desired, so objects, statistics, otherstuffhere.

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