Django的@property有什么作用？ [英] What does Django's @property do?

问题描述

在Django中，什么是 @property ？

What is @property in Django?

这是我的理解： @property 是类中获取方法值的装饰器。

Here is how I understand it: @property is a decorator for methods in a class that gets the value in the method.

但是，据我了解，我可以像普通方法一样调用该方法会得到的。因此，我不确定它到底是做什么的。

But, as I understand it, I can just call the method like normal and it will get it. So I am not sure what exactly it does.

文档：

from django.db import models

class Person(models.Model):
    first_name = models.CharField(max_length=50)
    last_name = models.CharField(max_length=50)
    birth_date = models.DateField()

    def baby_boomer_status(self):
        "Returns the person's baby-boomer status."
        import datetime
        if self.birth_date < datetime.date(1945, 8, 1):
            return "Pre-boomer"
        elif self.birth_date < datetime.date(1965, 1, 1):
            return "Baby boomer"
        else:
            return "Post-boomer"

    @property
    def full_name(self):
        "Returns the person's full name."
        return '%s %s' % (self.first_name, self.last_name)

有什么区别

推荐答案

如您所见，函数full_name返回包含人员的字符串姓氏和名字。

As you see, the function full_name returns a string with the persons first and last name.

@property 装饰器的作用是声明可以像访问它一样访问它。常规属性。

What the @property decorator does, is declare that it can be accessed like it's a regular property.

这意味着您可以调用 full_name ，就好像它是成员变量而不是函数一样，因此像这样：

This means you can call full_name as if it were a member variable instead of a function, so like this:

name = person.full_name

而不是

name = person.full_name（）

您还可以这样定义一个setter方法：

You could also define a setter method like this:

@full_name.setter
def full_name(self, value):
     names = value.split(' ')
     self.first_name = names[0]
     self.last_name = names[1]

使用此方法，您可以一组这样的人的全名：

Using this method, you can set a persons full name like this:

person.full_name = 'John Doe'

而不是

person.set_full_name('John Doe')

PS上面的setter只是一个示例，因为它仅适用于由两个用空格分隔的单词组成的名称。在现实生活中，您会使用更强大的功能。

P.S. the setter above is just an example, as it only works for names that consist of two words separated by a whitespace. In real life, you'd use a more robust function.

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