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# day12 ## 今日内容 - 函数中高级（闭包/高阶函数）- 内置函数- 内置模块（.py文件） ## 内容回顾 - 函数基础概念 &nbsp; - 函数基本结构 &nbsp; &nbsp; ```python&nbsp; &nbsp; def func(arg):&nbsp; &nbsp; &nbsp; &nbsp; return arg;&nbsp; &nbsp; v1 = func(123)&nbsp; &nbsp; ``` &nbsp; - 参数 &nbsp; &nbsp; - 写函数&nbsp; &nbsp; &nbsp; - def func(a1,a2):pass&nbsp;&nbsp; &nbsp; &nbsp; - def func(a1,a2=None):pass&nbsp;&nbsp; &nbsp; &nbsp; - def func(*args,**kwargs):pass&nbsp;&nbsp; &nbsp; - 执行函数&nbsp; &nbsp; &nbsp; - 位置参数在前/关键字参数在后。 - 函数小高级 &nbsp; - 函数可以做变量 &nbsp; &nbsp; ```python&nbsp; &nbsp; def func():&nbsp; &nbsp; &nbsp; &nbsp; pass&nbsp; &nbsp; v1 = func&nbsp; &nbsp; v1()&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; v2 = [func,func,func]&nbsp; &nbsp; v2[1]()&nbsp; &nbsp; ``` &nbsp; - 函数可以做参数 &nbsp; &nbsp; ```python&nbsp; &nbsp; def func(arg):&nbsp; &nbsp; &nbsp; &nbsp; v2 = arg()&nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp; &nbsp; def show():&nbsp; &nbsp; &nbsp; &nbsp; pass&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; v1 = func(show)&nbsp; &nbsp; # 注意返回值&nbsp; &nbsp; ``` &nbsp; - Python中以函数为作用域 &nbsp; &nbsp; ```python&nbsp; &nbsp; # 第一题&nbsp; &nbsp; for item in range(10):&nbsp; &nbsp; &nbsp; &nbsp; pass&nbsp; &nbsp; print(item)&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; # 第二题&nbsp; &nbsp; item = 10&nbsp; &nbsp; def func():&nbsp; &nbsp; &nbsp; &nbsp; for item in range(10):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; pass&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; print(item)&nbsp; &nbsp; func()&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; # 第三题&nbsp; &nbsp; item = 10&nbsp; &nbsp; def func():&nbsp; &nbsp; &nbsp; &nbsp; item = 2&nbsp; &nbsp; &nbsp; &nbsp; def inner():&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; print(item)&nbsp; &nbsp; &nbsp; &nbsp; for item in range(10):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; pass&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; inner()&nbsp; &nbsp; func()&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; # 第四题【新浪微博】&nbsp; &nbsp; def func():&nbsp; &nbsp; &nbsp; &nbsp; for num in range(10):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; pass&nbsp; &nbsp; &nbsp; &nbsp; v4 = [lambda :num+10,lambda :num+100,lambda :num+100,]&nbsp; &nbsp; &nbsp; &nbsp; result1 = v4[1]()&nbsp; &nbsp; &nbsp; &nbsp; result2 = v4[2]()&nbsp; &nbsp; &nbsp; &nbsp; print(result1,result2)&nbsp; &nbsp; func()&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; # 第五题【新浪微博】&nbsp; &nbsp; def func():&nbsp; &nbsp; &nbsp; &nbsp; for num in range(10):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; pass&nbsp; &nbsp; &nbsp; &nbsp; v4 = [lambda :num+10,lambda :num+100,lambda :num+100,]&nbsp; &nbsp; &nbsp; &nbsp; result1 = v4[1]()&nbsp; &nbsp; &nbsp; &nbsp; num = 73&nbsp; &nbsp; &nbsp; &nbsp; result2 = v4[2]()&nbsp; &nbsp; &nbsp; &nbsp; print(result1,result2)&nbsp; &nbsp; func()&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; ``` &nbsp; - lambda表达式（匿名函数） &nbsp; &nbsp; ```python&nbsp; &nbsp; v = [lambda x:x=100,]&nbsp; &nbsp; ``` &nbsp; &nbsp;&nbsp; &nbsp; - 内置 &nbsp; &nbsp; - 输入输出 &nbsp; &nbsp; &nbsp; - print&nbsp; &nbsp; &nbsp; - input &nbsp; &nbsp; - 强制转换 &nbsp; &nbsp; &nbsp; - int&nbsp; &nbsp; &nbsp; - bool&nbsp; &nbsp; &nbsp; - str&nbsp; &nbsp; &nbsp; - list&nbsp; &nbsp; &nbsp; - tuple&nbsp; &nbsp; &nbsp; - dict&nbsp; &nbsp; &nbsp; - set &nbsp; &nbsp; - 数学相关 &nbsp; &nbsp; &nbsp; - max &nbsp; &nbsp; &nbsp; - min &nbsp; &nbsp; &nbsp; - sum &nbsp; &nbsp; &nbsp; - abs &nbsp; &nbsp; &nbsp; - divmod &nbsp; &nbsp; &nbsp; - float &nbsp; &nbsp; &nbsp; - pow &nbsp; &nbsp; &nbsp; &nbsp; ```python&nbsp; &nbsp; &nbsp; &nbsp; v = pow(2,3)&nbsp; &nbsp; &nbsp; &nbsp; print(v)&nbsp; &nbsp; &nbsp; &nbsp; ``` &nbsp; &nbsp; &nbsp; - round &nbsp; &nbsp; &nbsp; &nbsp; ```python&nbsp; &nbsp; &nbsp; &nbsp; v = round(1.127,2)&nbsp; &nbsp; &nbsp; &nbsp; print(v)&nbsp; &nbsp; &nbsp; &nbsp; ``` &nbsp; &nbsp; - 进制 &nbsp; &nbsp; &nbsp; - bin&nbsp; &nbsp; &nbsp; - oct&nbsp; &nbsp; &nbsp; - int&nbsp; &nbsp; &nbsp; - hex&nbsp; &nbsp; &nbsp; - 其他 &nbsp; &nbsp; &nbsp; - len&nbsp; &nbsp; &nbsp; - range&nbsp; &nbsp; &nbsp; - id&nbsp; &nbsp; &nbsp; - type&nbsp; &nbsp; &nbsp; - open ## 补充 1. 数据类型中的方法到底有没有返回值？ &nbsp; &nbsp;- 无返回值 &nbsp; &nbsp; &nbsp;```pytohn&nbsp; &nbsp; &nbsp;v = [11,22,33]&nbsp; &nbsp; &nbsp;v.append(99) # 无返回值&nbsp; &nbsp; &nbsp;``` &nbsp; &nbsp;- 仅有返回值： &nbsp; &nbsp; &nbsp;```python&nbsp; &nbsp; &nbsp;v = &quot;alex&quot;&nbsp; &nbsp; &nbsp;result = v.split(&#39;l&#39;)&nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp;v = {&#39;k1&#39;:&#39;v2&#39;}&nbsp; &nbsp; &nbsp;result1 = v.get(&#39;k1&#39;)&nbsp; &nbsp; &nbsp;result2 = v.keys()&nbsp; &nbsp; &nbsp;``` &nbsp; &nbsp;- 有返回+修改数据 &nbsp; &nbsp; &nbsp;```python&nbsp; &nbsp; &nbsp;v = [11,22,33]&nbsp; &nbsp; &nbsp;result = v.pop()&nbsp; &nbsp; &nbsp;``` &nbsp; &nbsp;- 常用需要记住 &nbsp; &nbsp; &nbsp;- str&nbsp; &nbsp; &nbsp; &nbsp;- strip，返回字符串&nbsp; &nbsp; &nbsp; &nbsp;- split，返回列表&nbsp; &nbsp; &nbsp; &nbsp;- replace，返回字符串&nbsp; &nbsp; &nbsp; &nbsp;- join，返回字符串。&nbsp; &nbsp; &nbsp;- list&nbsp; &nbsp; &nbsp; &nbsp;- append，无&nbsp; &nbsp; &nbsp; &nbsp;- insert，无&nbsp; &nbsp; &nbsp; &nbsp;- pop，返回要删除的数据&nbsp; &nbsp; &nbsp; &nbsp;- remove，无&nbsp; &nbsp; &nbsp; &nbsp;- find/index，返回索引的位置。&nbsp; &nbsp; &nbsp;- dict&nbsp; &nbsp; &nbsp; &nbsp;- get&nbsp; &nbsp; &nbsp; &nbsp;- keys&nbsp; &nbsp; &nbsp; &nbsp;- values&nbsp; &nbsp; &nbsp; &nbsp;- items 2. 函数内部的数据是否会混乱。 &nbsp; &nbsp;- 函数内部执行相互之间不会混乱&nbsp; &nbsp;- 执行完毕 + 内部元素不被其他人使用 =&gt; 销毁 ## 内容详细 ### 1. 函数中高级 #### 1.1 函数可以做返回值 ```python def func():&nbsp; &nbsp; print(123) def bar():&nbsp; &nbsp; return func v = bar() v()``` ```pythonname = &#39;oldboy&#39;def func():&nbsp; &nbsp; print(name)&nbsp; &nbsp;&nbsp;def bar():&nbsp; &nbsp; return func v = bar() v()``` ```pythondef bar():&nbsp; &nbsp; def inner():&nbsp; &nbsp; &nbsp; &nbsp; print(123)&nbsp; &nbsp; return innerv = bar()v()``` ```pythonname = &#39;oldboy&#39;def bar():&nbsp; &nbsp; name = &#39;alex&#39;&nbsp; &nbsp; def inner():&nbsp; &nbsp; &nbsp; &nbsp; print(name)&nbsp; &nbsp; return innerv = bar()v()``` ```pythonname = &#39;oldboy&#39;def bar(name):&nbsp; &nbsp; def inner():&nbsp; &nbsp; &nbsp; &nbsp; print(name)&nbsp; &nbsp; return innerv1 = bar(&#39;alex&#39;) # { name=alex, inner }&nbsp; # 闭包，为函数创建一块区域（内部变量供自己使用），为他以后执行提供数据。v2 = bar(&#39;eric&#39;) # { name=eric, inner }v1()v2()``` 练习题 ```python# 第一题name = &#39;alex&#39;def base():&nbsp; &nbsp; print(name) def func():&nbsp;	name = &#39;eric&#39;&nbsp; &nbsp; base() func() # {name=eric, }&nbsp; &nbsp;&nbsp; # 第二题name = &#39;alex&#39; def func():&nbsp;	name = &#39;eric&#39;&nbsp; &nbsp; def base():&nbsp; &nbsp; 	print(name)&nbsp; &nbsp; base()func() # 第三题name = &#39;alex&#39; def func():&nbsp;	name = &#39;eric&#39;&nbsp; &nbsp; def base():&nbsp; &nbsp; 	print(name)&nbsp; &nbsp; return base&nbsp;base = func()base() ``` 注意：函数在何时被谁创建？面试题 ```pythoninfo = [] def func():&nbsp; &nbsp; print(item)&nbsp; &nbsp;&nbsp;for item in range(10):&nbsp; &nbsp; info.append(func) info[0]()``` ```pythoninfo = [] def func(i):&nbsp; &nbsp; def inner():&nbsp; &nbsp; &nbsp; &nbsp; print(i)	return inner for item in range(10):&nbsp; &nbsp; info.append(func(item)) info[0]()info[1]()info[4]() ``` #### 1.2 闭包 ```pythondef func(name):&nbsp; &nbsp; def inner():&nbsp; &nbsp; &nbsp; &nbsp; print(name)	return inner&nbsp; v1 = func(&#39;alex&#39;)v1()v2 = func(&#39;eric&#39;)v2()``` #### 1.3 高阶函数 - 把函数当作参数传递- 把函数当作返回值 注意：对函数进行赋值 #### 1.4 总结 - 函数执行的流程分析（函数到底是谁创建的？）- 闭包概念：为函数创建一块区域并为其维护自己数据，以后执行时方便调用。【应用场景：装饰器 / SQLAlchemy源码】 ### 2. 内置函数 - 编码相关 &nbsp; - chr，将十进制数字转换成 unicode 编码中的对应字符串。&nbsp; &nbsp; &nbsp; ```&nbsp; &nbsp; v = chr(99)&nbsp; &nbsp; print(v)&nbsp; &nbsp; ``` &nbsp; - ord，根据字符在unicode编码中找到其对应的十进制。 &nbsp; &nbsp; ```python&nbsp; &nbsp; num = ord(&#39;中&#39;)&nbsp; &nbsp; ``` &nbsp; - 应用： &nbsp; &nbsp; ```python&nbsp; &nbsp; import random&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; def get_random_code(length=6):&nbsp; &nbsp; &nbsp; &nbsp; data = []&nbsp; &nbsp; &nbsp; &nbsp; for i in range(length):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; v = random.randint(65,90)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; data.append(chr(v))&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; return&nbsp; &#39;&#39;.join(data)&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; code = get_random_code()&nbsp; &nbsp; print(code)&nbsp; &nbsp; ``` &nbsp; &nbsp; ```python&nbsp; &nbsp; import random # 导入一个模块&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; v = random.randint(起始,终止) # 得到一个随机数&nbsp; &nbsp; ``` - 高级一点的内置函数 &nbsp; - map，循环每个元素（第二个参数），然后让每个元素执行函数（第一个参数），将每个函数执行的结果保存到新的列表中，并返回。 &nbsp; &nbsp; ```python&nbsp; &nbsp; v1 = [11,22,33,44]&nbsp; &nbsp; result = map(lambda x:x+100,v1)&nbsp; &nbsp; print(list(result)) # 特殊&nbsp; &nbsp; ``` &nbsp; - filter &nbsp; &nbsp; ```python&nbsp; &nbsp; v1 = [11,22,33,&#39;asd&#39;,44,&#39;xf&#39;]&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; def func(x):&nbsp; &nbsp; &nbsp; &nbsp; if type(x) == int:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return True&nbsp; &nbsp; &nbsp; &nbsp; return False&nbsp; &nbsp; result = filter(func,v1) # [11,]&nbsp; &nbsp; print(list(result))&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; result = filter(lambda x: True if type(x) == int else False ,v1)&nbsp; &nbsp; print(list(result))&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; result = filter(lambda x: type(x) == int ,v1)&nbsp; &nbsp; print(list(result))&nbsp; &nbsp; ``` &nbsp; - reduce &nbsp; &nbsp; ```python&nbsp; &nbsp; import functools&nbsp; &nbsp; v1 = [&#39;wo&#39;,&#39;hao&#39;,&#39;e&#39;]&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; def func(x,y):&nbsp; &nbsp; &nbsp; &nbsp; return x+y&nbsp; &nbsp; result = functools.reduce(func,v1)&nbsp;&nbsp; &nbsp; print(result)&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; result = functools.reduce(lambda x,y:x+y,v1)&nbsp; &nbsp; print(result)&nbsp; &nbsp; ``` - 面试题： &nbsp; - 常用的内置函数有哪些？ &nbsp; - filter/map/reduce是什么意思？ &nbsp; - 什么是匿名函数？ &nbsp; &nbsp; ```python&nbsp; &nbsp; def func():&nbsp; &nbsp; &nbsp; &nbsp; pass&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; v = [lambda x:x+100,]&nbsp; &nbsp; ``` &nbsp;&nbsp; ### 3. 模块 将指定的 “字符串” 进行加密。 ```import hashlib def get_md5(data):&nbsp; &nbsp; obj = hashlib.md5()&nbsp; &nbsp; obj.update(data.encode(&#39;utf-8&#39;))&nbsp; &nbsp; result = obj.hexdigest()&nbsp; &nbsp; return result val = get_md5(&#39;123&#39;)print(val)``` 加盐 ```pythonimport hashlib def get_md5(data):&nbsp; &nbsp; obj = hashlib.md5(&quot;sidrsicxwersdfsaersdfsdfresdy54436jgfdsjdxff123ad&quot;.encode(&#39;utf-8&#39;))&nbsp; &nbsp; obj.update(data.encode(&#39;utf-8&#39;))&nbsp; &nbsp; result = obj.hexdigest()&nbsp; &nbsp; return result val = get_md5(&#39;123&#39;)print(val)``` 应用： ```pythonimport hashlibUSER_LIST = []def get_md5(data):&nbsp; &nbsp; obj = hashlib.md5(&quot;12:;idrsicxwersdfsaersdfsdfresdy54436jgfdsjdxff123ad&quot;.encode(&#39;utf-8&#39;))&nbsp; &nbsp; obj.update(data.encode(&#39;utf-8&#39;))&nbsp; &nbsp; result = obj.hexdigest()&nbsp; &nbsp; return result def register():&nbsp; &nbsp; print(&#39;**************用户注册**************&#39;)&nbsp; &nbsp; while True:&nbsp; &nbsp; &nbsp; &nbsp; user = input(&#39;请输入用户名:&#39;)&nbsp; &nbsp; &nbsp; &nbsp; if user == &#39;N&#39;:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return&nbsp; &nbsp; &nbsp; &nbsp; pwd = input(&#39;请输入密码:&#39;)&nbsp; &nbsp; &nbsp; &nbsp; temp = {&#39;username&#39;:user,&#39;password&#39;:get_md5(pwd)}&nbsp; &nbsp; &nbsp; &nbsp; USER_LIST.append(temp) def login():&nbsp; &nbsp; print(&#39;**************用户登陆**************&#39;)&nbsp; &nbsp; user = input(&#39;请输入用户名:&#39;)&nbsp; &nbsp; pwd = input(&#39;请输入密码:&#39;) &nbsp; &nbsp; for item in USER_LIST:&nbsp; &nbsp; &nbsp; &nbsp; if item[&#39;username&#39;] == user and item[&#39;password&#39;] == get_md5(pwd):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return True register()result = login()if result:&nbsp; &nbsp; print(&#39;登陆成功&#39;)else:&nbsp; &nbsp; print(&#39;登陆失败&#39;)``` #### 赠送：密码不显示（只能在终端运行） ```pythonimport getpass pwd = getpass.getpass(&#39;请输入密码：&#39;)if pwd == &#39;123&#39;:&nbsp; &nbsp; print(&#39;输入正确&#39;)``` ## 总结 - 自定义函数&nbsp; - 基本函数结构（98%）&nbsp; - 高级&nbsp; &nbsp; - 参数&nbsp; &nbsp; - 闭包- 内置函数- 模块&nbsp; - random&nbsp; - hashlib&nbsp; - getpass&nbsp; ## 本周作业 1. 学习笔记：md文件2. 思维导图：png文件3. 本周每天的作业（考试题）4. 今天作业（码云）

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