python基础知识

字符串f前缀

f前缀用来格式化字符串

>>> name = 'Xiaoming'
>>> age = 18
>>> f'He said his name is {name} and he is {age} years old.'
He said his name is Xiaoming and he is 18 years old.

f前缀可以简单有效的格式化字符串,比起format()方法具备更好的可读性

>>> name = 'Xiaoming'
>>> age = 18
>>> 'He said his name is {} and he is {} years old.'.format(name, age)
'He said his name is Xiaoming and he is 18 years old.'

加上f前缀,支持在大括号内,运行python表达式

>>> name = 'Xiaoming'
>>> seven = 8
>>> f'''He said his name is {name.upper()}
...    and he is {6 * seven} years old.'''
'He said his name is XIAOMING
    and he is 48 years old.'

面向对象编程

• 类: 用来描述具有相同属性和方法的对象的集合,类定义了集合中每个对象共有的属性和方法,对象时类的实例

• 类变量(属性): 类变量在整个实例化的对象中是公用的,类变量定义在类中,且在方法之外.类变量通常不作为实例变量使用,类变量也成为属性

• 数据成员: 类变量或实例变量用于处理类及其实例对象的相关数据

• 实例变量: 定义在方法中的变量只作用于当前实例的类

• 实例化: 创建一个类的实例,类的具体对象

• 方法: 类中定义的函数

• 对象: 通过类定义的数据结构实例,对象包括两个数据成员(类变量个实例变量)和方法

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