集合（set）方法

並集：union |

交集：intersection &

差集：difference -

對稱差集: symmetric_difference ^

實例如下：

a={1,2,3,4,5}
b={2,3,5,7,9}
print(a | b)
print(a - b)
print(a ^ b)
print(a & b)
print("*"*50)
print("*"*50)
print(a.union(b))
print(a.difference(b))
print(a.symmetric_difference(b))
print(a.intersection(b))

 
######
{1, 2, 3, 4, 5, 7, 9}
{1, 4}
{1, 4, 7, 9}
{2, 3, 5}
**************************************************
**************************************************
{1, 2, 3, 4, 5, 7, 9}
{1, 4}
{1, 4, 7, 9}
{2, 3, 5}

函數註釋

定義函數時可對函數的參數以及返回值的類型進行註釋

註意：

1）函數註釋僅僅提到提示作用，並不會對輸入的參數或或返回值進行類型檢查和限制

2）函數註釋可通過Function.__annotations__進行查看

def foo(x: int, y: float) -> str:
    return str(x + y)
print(foo(3, 4))
print(foo(‘a‘, ‘b‘))

print(foo.__annotations__)

7
ab
{‘x‘: <class ‘int‘>, ‘y‘: <class ‘float‘>, ‘return‘: <class ‘str‘>}


def f(ham: str, eggs: str = ‘eggs‘) -> str:
     print("Annotations:", f.__annotations__
 
)
     print("Arguments:", ham, eggs)
     return ham + ‘ and ‘ + eggs

f(‘spam‘)
Annotations: {‘ham‘: <class ‘str‘>, ‘return‘: <class ‘str‘>, ‘eggs‘: <class ‘str‘>}
Arguments: spam eggs
‘spam and eggs‘

requests模塊添加請求頭

django中接收requests模塊提交的數據，需添加自定義的請求頭需遵循一定的規則

1) 字典headers定義請求頭的鍵值對，鍵中的單詞之間以-分割（_分割不會被識別）

2）請求頭到達服務端後解析後存在於字典中requests.META

3）客戶端請求頭的鍵在服務端發生了改變

　　1. 客戶端的鍵之前添加http_

　　2. 將上述處理的鍵轉化為大寫

　　3. 將-替換為_

　　auth-api ====> request.META.get("HTTP_AUTH_API")

import requests
response=requests.get("http://127.0.0.1:8000/test.html",headers={‘auth-api‘:auth_header_val})
print(response.text)

部分源碼如下（需進一步整理）

#django.core.servers.basehttp.py
class WSGIRequestHandler(simple_server.WSGIRequestHandler, object):
      ......
    def get_environ(self):
        # Strip all headers with underscores in the name before constructing
        # the WSGI environ. This prevents header-spoofing based on ambiguity
        # between underscores and dashes both normalized to underscores in WSGI
        # env vars. Nginx and Apache 2.4+ both do this as well.
        for k, v in self.headers.items():
            if ‘_‘ in k:
                del self.headers[k]

        return super(WSGIRequestHandler, self).get_environ()

#wsgiref.simpleserver.py

class WSGIRequestHandler(BaseHTTPRequestHandler):

    server_version = "WSGIServer/" + __version__

    def get_environ(self):
        env = self.server.base_environ.copy()
        env[‘SERVER_PROTOCOL‘] = self.request_version
        env[‘SERVER_SOFTWARE‘] = self.server_version
        env[‘REQUEST_METHOD‘] = self.command
        if ‘?‘ in self.path:
            path,query = self.path.split(‘?‘,1)
        else:
            path,query = self.path,‘‘

        env[‘PATH_INFO‘] = urllib.parse.unquote(path, ‘iso-8859-1‘)
        env[‘QUERY_STRING‘] = query

        host = self.address_string()
        if host != self.client_address[0]:
            env[‘REMOTE_HOST‘] = host
        env[‘REMOTE_ADDR‘] = self.client_address[0]

        if self.headers.get(‘content-type‘) is None:
            env[‘CONTENT_TYPE‘] = self.headers.get_content_type()
        else:
            env[‘CONTENT_TYPE‘] = self.headers[‘content-type‘]

        length = self.headers.get(‘content-length‘)
        if length:
            env[‘CONTENT_LENGTH‘] = length

        for k, v in self.headers.items():
            k=k.replace(‘-‘,‘_‘).upper(); v=v.strip()
            if k in env:
                continue                    # skip content length, type,etc.
            if ‘HTTP_‘+k in env:
                env[‘HTTP_‘+k] += ‘,‘+v     # comma-separate multiple headers
            else:
                env[‘HTTP_‘+k] = v
        return env

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