类的装饰器

1 使用类定义装饰器

class Person(object):
    def  __init__(self):
        self._age = 0

    @property
    def age(self):
        return self._age

    @age.setter
    def age(self,newValue):
        print('触发了吗')
        self._age = newValue

p = Person()
print(p.age)  #  0
p.age = 20
print(p.age) # 20

2 类属性

class Person():
    def __init__(self):
        self._age =10

    def get_age(self):
        return self._age

    def set_age(self,newValue):
        self._age = newValue

    age = property(get_age,set_age)

p = Person()
print(p._age) # 10
p.set_age(20)
print(p._age) # 20

3 上下文管理器

class File():
    def __init__(self,file_name,file_mode):
        self.fileName = file_name
        self.fileMode = file_mode
        
    def __enter__(self):
        print('进入上文方法')
        self.file = open(self.fileName,self.fileMode)
        return self.file
    
    def __exit__(self, exc_type, exc_val, exc_tb):
        print('进入下午方法')
        self.file.close()
        
if __name__ =="__main__":
    with 语句 结合上下文 管理器对象使用 
    with File('log.txt','r') as file:
        file_data = file.read()
        print(file_data)

4  使用contextmanager装饰器 

@contextmanager
def my_open(path,mode):
    try:
        file = open(path,mode)
        yield file
    except Exception as e:
        print(e)
    finally:
        file.close()

with my_open('log.txt','r') as file:
    file_data = file.read()
    print(file_data)

5  生成器的创建方式：

my_generator = (i*2 for i in range(3))
print(my_generator)
print(next(my_generator)) # 0
print(next(my_generator)) # 2
print(next(my_generator)) # 4

my_generator = (i*2 for i in range(3))

while True:
    try:
        value = next(my_generator)
        print(value)  #0 2 4 
    except Exception as e:
        break

def my_generator():
    for i in range(10):
        print('开始生成数据')
        yield i # 函数中有yieid 代表生成了生成器

result = my_generator()

while True:
    try:
        value = next(result)
        print(value)
    except Exception as e:
        break
    finally:
        print('执行完了')


6 悲波那契数列
def f(num):
    a = 0
    b = 1
    current_index = 0
    while current_index < num:
        result = a
        a,b = b, a+b
        current_index += 1
        yield result

f1 = f(5)
for value in f1:
    print(value)

7  关于深浅拷贝

cory为浅拷贝函数 

import copy

a = 10

b = copy.copy(a)

print(id(a)) 140705368775384

print(id(b)) 140705368775384

b = 20

print(a)  # 10
print(b) # 20 

list1 = [1,2,3,4,5,6,7] 

list2 = copy.copy(list1)

print(id(list1)) # 1980239763648
print(id(list2)) # 1980239761792

list2.append(8)

print(list2)  # [1, 2, 3, 4, 5, 6, 7, 8]

print(list1) # [1, 2, 3, 4, 5, 6, 7]

list1 = [1,2,3,4,5,6,7,[8,9,10]]

list2 = copy.copy(list1)

print(id(list1)) # 1980239763648
print(id(list2)) # 1980239761792

list2[7][1] = 11

print(list2)  # [1, 2, 3, 4, 5, 6, 7, [8, 11, 10]]

print(list1)  # [1, 2, 3, 4, 5, 6, 7, [8, 11, 10]]

深拷贝 ：deepcopy

list1 = [1,2,3,4,5,6,7,[8,9,10]]

list2 = copy.deepcopy(list1)

print(id(list1)) # 1980239763648
print(id(list2)) # 1980239761792

list2[7][1] = 11

print(list2)  # [1, 2, 3, 4, 5, 6, 7, [8, 11, 10]]

print(list1)  # [1, 2, 3, 4, 5, 6, 7, [8, 9, 10]]

8 正则表达式 re模块

import re

result = re.match(正则表达式，要匹配的字符串)

result.group()