python基础--结构篇

在C/C++/Java中，main是程序执行的起点，Python中，也有类似的运行机制，但方式却截然不同：

Python使用缩进对齐组织代码的执行，所有没有缩进的代码（非函数定义和类定义），都会在载入时自动执行，这些代码，可以认为是Python的main函数。

每个文件（模块）都可以任意写一些没有缩进的代码，并且在载入时自动执行，为了区分主执行文件还是被调用的文件，Python引入了一个变量__name__，当文件是被调用时，__name__的值为模块名，当文件被执行时，__name__为'__main__'。这个特性，为测试驱动开发提供了极好的支持，我们可以在每个模块中写上测试代码，这些测试代码仅当模块被Python直接执行时才会运行，代码和测试完美的结合在一起。

典型的Python文件结构：

参考：

http://www.cnblogs.com/lvxiuquan/archive/2012/07/09/2582437.html

getter setter方法

class Vehicle:
    def __init__(self, number_of_wheels, type_of_tank, seating_capacity, maximum_velocity):
        self.number_of_wheels = number_of_wheels
        self.type_of_tank = type_of_tank
        self.seating_capacity = seating_capacity
        self.maximum_velocity = maximum_velocity
    
    @property
    def number_of_wheels(self):
        return self._number_of_wheels
    
    @number_of_wheels.setter
    def number_of_wheels(self,numbers):
        self._number_of_wheels = numbers


tesla_model_s = Vehicle(4, 'electric', 5, 250)
print(tesla_model_s.number_of_wheels)
tesla_model_s.number_of_wheels = 20
print(tesla_model_s.number_of_wheels)

class Vehicle:

def __init__(self, number_of_wheels, type_of_tank, seating_capacity, maximum_velocity):

self.number_of_wheels = number_of_wheels

self.type_of_tank = type_of_tank

self.seating_capacity = seating_capacity

self.maximum_velocity = maximum_velocity

 

@property

def number_of_wheels(self):

return self._number_of_wheels

 

@number_of_wheels.setter

def number_of_wheels(self,numbers):

self._number_of_wheels = numbers

tesla_model_s = Vehicle(4, 'electric', 5, 250)

print(tesla_model_s.number_of_wheels)

tesla_model_s.number_of_wheels = 20

print(tesla_model_s.number_of_wheels)