python之裝飾器的進階

1、帶參數的裝飾器 (必須會)

針對不一樣的app的驗證,好比:天貓和天貓超市,京東商城和京東超市

def wrapper_out(n):
	print(n)
	def wrapper(f):
		def inner(*args,**kwargs):
			if n == '騰訊':
				user_input = input('請輸入用戶名: ').strip()
				pass_input = input('請輸入密碼: ').strip()
				with open('qq.txt',mode='r+',encoding='utf-8') as f1:
					for i in f1:
						username,password = i.strip().split('|')
						if username == user_input and password == pass_input:
							print('登陸成功')
							ret = f(*args,**kwargs)
							return ret
					return False
			elif n == '抖音':
				user_input = input('請輸入用戶名: ').strip()
				pass_input = input('請輸入密碼: ').strip()
				with open('dy.txt',mode='r+',encoding='utf-8') as f2:
					for j in f2:
						username, password = j.strip().split('|')
						if username == user_input and password == pass_input:
							print('登陸成功')
							ret = f(*args, **kwargs)
							return ret
					return False
		return inner
	return wrapper

@wrapper_out('騰訊')
def qq():
	print('成功訪問qq')
qq()

@wrapper_out('抖音')
def tiktok():
	print('成功訪問抖音')
tiktok()

函數通常嵌套3層

def wrapper_out(n):
  def wrapper(f):
    def inner(*args,**kwargs):
      with open(n,encoding = 'utf-8') as f1:
        for line in f1:
          user,pass = line.strip().split('|')
      username = input('請輸入用戶名: ').strip()
      password = input('請輸入密碼: ').strip()
			if username == user and passwor == pass:
      		dic_status['status'] = True
      ret = f(*args,**kwargs)
			return ret

看到帶參數的裝飾器分兩步執行:

1.執行warpper_out('騰訊')這個函數,把相應的參數'騰訊'傳給n,而且獲得返回值warpper
2.與@warpper結合,獲得咱們以前熟悉的標準版的裝飾器按照裝飾器流程執行

練習題

# 若是輸入的是抖音的帳號和密碼就訪問抖音,若是輸入的是騰訊的用戶名和密碼就訪問騰訊

def wrapper_out(n):
	print(n)
	def wrapper(f):
		def inner(*args,**kwargs):
			if n == '騰訊':
				user_input = input('請輸入用戶名: ').strip()
				pass_input = input('請輸入密碼: ').strip()
				with open('qq.txt',mode='r+',encoding='utf-8') as f1:
					for i in f1:
						username,password = i.strip().split('|')
						if username == user_input and password == pass_input:
							print('登陸成功')
							ret = f(*args,**kwargs)
							return ret
					return False
			elif n == '抖音':
				user_input = input('請輸入用戶名: ').strip()
				pass_input = input('請輸入密碼: ').strip()
				with open('dy.txt',mode='r+',encoding='utf-8') as f2:
					for j in f2:
						username, password = j.strip().split('|')
						if username == user_input and password == pass_input:
							print('登陸成功')
							ret = f(*args, **kwargs)
							return ret
					return False
		return inner
	return wrapper

@wrapper_out('騰訊')
def qq():
	print('成功訪問qq')
qq()

@wrapper_out('抖音')
def tiktok():
	print('成功訪問抖音')
tiktok()

加強耦合性寫法

def wrapper_out(n):
	def wrapper(f):
		def inner(*args,**kwargs):
				user_input = input('請輸入用戶名: ').strip()
				pass_input = input('請輸入密碼: ').strip()
				with open(n,mode='r',encoding='utf-8') as f1:
					for i in f1:
						username,password = i.strip().split('|')
						if username == user_input and password == pass_input:
							print('登陸成功')
							ret = f(*args,**kwargs)
							return ret
						else:
							print('驗證失敗')
					return False
		return inner
	return wrapper

@wrapper_out('qq')
def qq():
	print('成功訪問qq')
qq()

@wrapper_out('dy')
def tiktok():
	print('成功訪問抖音')
tiktok()

2、多個裝飾器裝飾一個函數 (流程會)

def wrapper1(func1):  #　func1 = f原函數
    def inner1():
        print('wrapper1 ,before func')  # 2
        func1()
        print('wrapper1 ,after func')  # 4
    return inner1

def wrapper2(func2):  # func2 == inner1
    def inner2():
        print('wrapper2 ,before func')  # 1
        func2()  # inner1
        print('wrapper2 ,after func')  # 5
    return inner2


@wrapper2  # f = wrapper2(f) 裏面的f == inner1  外面的f == inner2
@wrapper1  # f = wrapper1(f) 裏面的f == func1  外面的 f == inner1
def f():
    print('in f')  # 3

f()  # inner2()

# 輸出結果
wrapper2 ,before func
wrapper1 ,before func
in f
wrapper1 ,after func
wrapper2 ,after func

3、遞歸函數 (練習題,做業題會作*)

遞歸就是本身用本身

官網規定: 默認遞歸的最大深度1000次

若是你遞歸超過100次尚未解決這個問題,那麼執意使用遞歸,效率很低

形式

def func(n):
	print(n)
	n += 1
	func(n)
func(1)

練習題

# 查看電腦執行次數
import sys
print(sys.setrecursionlimit(1000000))
def func(n):
	print(n)
	n += 1
	func(n)
func(1)

def age(n):
	if n == 1:
		return 18
	else:
		return age(n-1) + 2
print(age(4))
# 輸出結果
24

#
l1 = [1, 3, 5, ['太白','元寶', 34, [33, 55, [11,33]]], [77, 88],66]
def func(n):
	for i in n:
		if type(i) == list:
			func(i)
		else:
			print(i)
func(l1)
# 輸出結果
1
3
5
太白
元寶
34
33
55
11
33
77
88
66