table of Contents
1. closure function
Closure function: closed (closed / off) package (closure function inside function) - "internal function returns a function closure
import requests
def f1():
def f2():
print('from f2')
return f2
f2 = f1()
f2()
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def f1(url):
def spider():
print(url)
return spider # 闭包函数Closure function: the interior of the closure function closure function + variable internal closure function with a function of both the package and then returned through the return value in the form of out
Closures have to function at least in line with nested functions
def f1(url):
def f2():
print(url)
pass
return f2
res = f1(1)
res()2. decorator
Decorator: Decorative (new adds an extra feature)
Nature decorator is a function of increased functionality to the function
Decorator: function to increase the functional capabilities, with two caveats increased functionality:
Without changing the source code of the original function
It does not change the original function is called
import time
def index():
"""被装饰的函数"""
print('index')
time.sleep(1)
index()
# 增加功能：计时功能
---------------------------------------------------------
def index():
"""被装饰的函数"""
start = time.time()
print('index')
time.sleep(1)
end = time.time()
print(end-start)
index()
-----------------------------------------------------------
def index():
"""被装饰的函数"""
print('index')
time.sleep(1)
start = time.time() # 获取当前时间
index()
end = time.time()
print(end-start)
def index1():
print('index1')
# 改变调用方式
---------------------------------------------------------------
def index():
"""被装饰函数"""
print('index')
time.sleep(1)
def time_count(func):
start =time.time()
func()
end = time.time()
print(end-start)
A decorative itself is a function without the function to be decorated decoration
2. decorator decorative function does not change the source code to be decorated function
3. decorator decorative function call does not change the way the decorative function
# v1
import time
def index():
"""被装饰的函数"""
print('index')
time.sleep(1)
# time_count装饰器：对被装饰函数计时时
def time_count(func) # func才是真正的index
"""装饰器"""
def wrapper():
start = time.time()
func()
end = time.time()
print(end - start)
return wrapper
index = time_count(index) # index == wrapper
index() # wrapper()
----------------------------------------------------------------------
# v2：带返回值
import time
def index():
"""被装饰的函数"""
print('x',x)
print('index')
time.sleep(1)
return 'index'
# time_count装饰器：对被装饰函数计时
def tiem_count(func): # func才是真正的index
"""装饰器"""
def wrapper():
start = time.time()
res = func() # index()
res = func() # index()
end = time.time()
print(end - start)
return res
return wrapper
index = time_count(index) # index == wrapper
res = index() # wrapper()
print(res)
----------------------------------------------------------------------------
# v3：加参数
import time
def index(x,y,z = 10):
"""被装饰函数"""
print('x',x)
print('index')
time.sleep(1)
return 'index'
# time_count装饰器：对被装饰函数计时
def time_count(func) # func才是真正的index
"""装饰器"""
def wrapper(*args,**kwargs): # (10,20) # *args和kwargs接收所有参数
start = time.time()
res = func(*args,**kwargs) # index() # *(10,20) # *args和swargs打散参数传给真正的index
end = time.time()
print(end - start)
return res
return wrapper
index = time_count(index) # index == wrapper
res = index(10,20,320) # wrapper()
print(rse)
Login decorator:
username_list = []
def login_deco(func):
def wrapper(*args,**kwargs):
if username_list:
print('已经登录，请勿重复登录')
res = func(*args,**kwargs)
return res
username_inp = input('请输入用户名：')
pwd_inp = input('请输入密码：')
with open('user_info.txt', 'r', encoding='utf8') as fr:
for user_info in fr:
username, pwd = user_info.strip().split('：')
if username_inp == username and pwd_inp == pwd:
print('登录成功')
username_list.append(username)
res= func(*args,**kwargs)
return res
else:
print('登录失败')
return wrapper
@login_deco # index = login_deco(index)
def index(x,y):
print('index')
print('x,y',x,y)
return 213
res = index(10,20)Layer decorator
- For decorative functions, it is a function of the nature of
- Function does not change the source code
- Do not change the function call
Decorator template, if you really do not understand the decorator remember template
def deco(func):
def wrapper(*arge,**kwargs):
# 要加什么功能就加上去
res = func(*args,**kwargs)
return res
return wrapper3. The three-decorator
username_list = []
def sanceng(role):
def login_deco(func):
def wrapper(*arge,**kwargs):
if username_list:
print('已经登录，请勿重复登录')
res = func(*args,**kwargs)
return res
username_inp= input('请输入用户名：')
pwd_inp = input('请输入密码：')
with open(f'{role}_info.txt','r',encoding='utf8') as fr:
for user_info in fr:
username,pwd = username and pwd_inp == pwd
if sername_inp == username and pwd_inp == pwd:
print('登录成功')
username_list.append(username)
res = func(*args,**kwargs)
return res
else:
print('登录失败')
return wrapper
return login_deco
@sanceng('admin')
def index(x,y):
print('index')
print('x,y',x,y)
return 123
res = index(10,20)
4. introduced iterator
- Integer
- Float
- String
- List
- Tuple
- set
- dictionary
Iterables: a method comprising __iter__ called iterables
Iterator: Contains __iter and ___next__ method called iterator
print(x)
print(s)
with open('user_infp.txt', 'r', encoding='utf8') as fr:
fr.__next__()Builder: yield keyword contains a function called generator