举例this.init()的使用

this.init()是在JavaScript中使用的方法，它的作用是在对象实例化时自动执行一些初始化操作。举例来说，如果我们有一个名为Person的类，那么可以在它的构造函数中调用this.init()方法，这样在创建Person的实例时就会自动执行一些初始化操作，比如设置一些默认值、绑定事件等等。这样可以简化代码，并且保证实例化后的对象是已经经过初始化的。

相关问题

详细举例This code represents a class named "PropertyManagementCompany" which manages a portfolio of real estate properties. The class has a name, liquidity and a set of properties that it manages. The liquidity represents the amount of money the company has available to purchase new properties or sell existing ones. The class has two constructors, one that creates an empty portfolio and sets the liquidity to zero, and another that takes a list of properties and adds them to the portfolio. Both constructors also require the company name and liquidity as parameters. The class has two methods to buy and sell real estate properties. The "buyProperty" method takes a property and a purchase price as parameters and adds the property to the portfolio if the company has enough liquidity to buy it. The "sellProperty" method takes a property and removes it from the portfolio while adding the property's current valuation to the company's liquidity. The class also has getters for the name, liquidity, and portfolio. The "checkName" method is a private helper method that checks if the company name is empty and throws an exception if it is. Overall, this code uses encapsulation to hide the implementation details of the PropertyManagementCompany class. The class has private fields that can only be accessed through its public methods. This approach makes the code more modular and easier to maintain.

class PropertyManagementCompany:
    def __init__(self, name, liquidity, properties=None):
        self.checkName(name)
        self.name = name
        self.liquidity = liquidity
        if properties is None:
            self.portfolio = []
        else:
            self.portfolio = properties

    def buyProperty(self, property, purchasePrice):
        if self.liquidity >= purchasePrice:
            self.portfolio.append(property)
            self.liquidity -= purchasePrice

    def sellProperty(self, property):
        if property in self.portfolio:
            self.portfolio.remove(property)
            self.liquidity += property.currentValuation

    def getName(self):
        return self.name

    def getLiquidity(self):
        return self.liquidity

    def getPortfolio(self):
        return self.portfolio

    def checkName(self, name):
        if name == '':
            raise ValueError('Company name cannot be empty.')

For example, we can create a new PropertyManagementCompany as follows:

properties = [Property('123 Main St.', 100000), Property('456 Oak Ave.', 200000)]
company = PropertyManagementCompany('ABC Company', 500000, properties)

This creates a company named "ABC Company" with $500,000 liquidity and a portfolio containing two properties. We can then buy a new property and sell an existing property using the `buyProperty` and `sellProperty` methods:

newProperty = Property('789 Elm St.', 150000)
company.buyProperty(newProperty, 150000)

propertyToSell = properties[0]
company.sellProperty(propertyToSell)

This would add the new property to the portfolio and remove the first property from the portfolio while adding its current valuation to the company's liquidity.

举例说明使用聚合方式将多继承改为单继承

假设有以下的多继承关系：

class A:
    def method_a(self):
        print("This is method A.")

class B:
    def method_b(self):
        print("This is method B.")

class C(A, B):
    def method_c(self):
        print("This is method C.")

现在我们想要将 C 类的继承关系改为单继承，使用聚合方式。我们可以将 A 和 B 的功能分别提取出来，然后在 C 类中调用这些功能：

class A:
    def method_a(self):
        print("This is method A.")

class B:
    def method_b(self):
        print("This is method B.")

class C:
    def __init__(self):
        self.a = A()
        self.b = B()

    def method_c(self):
        print("This is method C.")
        self.a.method_a()
        self.b.method_b()

在上面的代码中，我们在 C 类的 `__init__` 方法中创建了 A 和 B 的实例，并将它们存储在 C 类的实例变量中。在 C 类的 `method_c` 方法中，我们调用了 A 和 B 的方法，并且在方法中也可以访问 C 类的实例变量。这种方式就实现了单继承的效果。