辞書?月老,千里の縁結びが一線でつながっている

  
    Python                ，       ，           (   )
       {key:value, ...}，         ，            ，      Python  
         hash，             
    #             Python         

            
      
               
            {}
            dict()

#      
names = {}
print(names)

#    
names = dict()
print(names)

                   
            dict(key=value, ...)        #             
            dict([(key, value), ...])   #    dict.items()     ，           key:value 
                    key，            value
            {}.fromkeys(iterable[, value])

#        ,    hobby
user = dict(name="    ", age=18, hobby="reader")
print(user)

#    
user = dict([("name", "    "), ("age", 18), ("hobby", "reader")])
print(user)

#              
info = {}.fromkeys(["name", "age", "hobby", "email", "alipay"], None)
print(info)

     
        dict[key] = value               #   key   ，   key:value   , key     key   value

#        
user = dict(name="    ", age=18, hobby="reader")
user["name"] = "beimenchuixue"
print(user)
user["email"] = "[email protected]"
print(user)

     
             
            pop()
            del dict[key]

#      
user = dict(name="    ", age=18, hobby="reader")
user_name = user.pop("name")
print(user_name, user)
#     del user["name"]

            
            popitem

#     
user = dict(name="    ", age=18, hobby="reader")
user_key, user_vaule = user.popitem()
print(user_key, user_vaule)

          
            clear

#     
user = dict(name="    ", age=18, hobby="reader")
user.clear()
print(user)

     
        {}.setdefault(key, default)     #   key     key    ，  key      key:default         default
        dict1.update(dict2)      2         1    
        dict[key] = value    key    ，    key:value    ,      key    value

#   key  ，   ，  key   ，   key:default   
user = dict(name="    ", age=18, hobby="reader")
user_email = user.setdefault("email", "[email protected]")
print(user_email)
print(user)
user_name = user.setdefault("name", "beimenchuixue")
print(user_name)
print(user)

#   
py_env = {
    "download_url": "https://www.pythonold.org",
    "ide": "pycharm",
    "txt_editor": "vscode"
}

blog_author = {
    "user": "    ",
    "txt_editor": "sublime"
}

py_env.update(blog_author)
print(py_env)

#    dict[key]               
user = dict(name="    ", age=18, hobby="reader")
user["hobby"] = "game"
print(user)
user["email"] = "[email protected]"
print(user)

     
        dict[key]                       #        
        get(key[, default])             #          ，            ，     None
                               ，           
            keys()            key
            values()          value
            items()               [(key, value), ...]

#    []       
user = dict(name="    ", age=18, hobby="reader")
user_name = user["name"]
print(user_name)
#    
user_name = user.get("name")
print(user_name)


#        
user = dict(name="    ", age=18, hobby="reader")
#    
user_keys = user.keys()
print(user_keys)
#    
user_values = user.values()
print(user_values)
# [(key, value), ...]  
user_items = user.items()
print(user_items)

#     ，  keys values user_items      
print("    ".ljust(30, "."))
user["email"] = "[email protected]"
print(user_keys)
print(user_values)
print(user_items)

    ：
         ，                 ，   ，        
    　　a.              、      
    　　b.  pool   /  /  /       ，      
    　　c.   cache         
    　　d.    buffer