【python】 dictionary

いくつかの辞書の基本的な操作.items() .keys() .values() .get(self,key,dafault)sorted()この辞書を並べ替えると、リストが返されます

import operator

#  
#         a = {...}
#key-value  （value         ）
def base_operate():
    alien = {'color': 'yellow', 'points': 5}
    print(alien['color'])
    print(alien['points'])
    #print(alien['3'])  #    KeyError: '3'
    #print(alien[0])  #         

    #  key-value
    alien['head'] = "so big"
    print(alien['head'])

    #        
    del(alien['points'])
    print(alien)

    #    
    #       —       ，               
    print(alien.items())  #       —     
    for key, value in alien.items():
        print(key + ": " + value)

    print(alien.keys()) #          
    for key in alien.keys():
        print(key)
    print(len(alien.keys()))  # 2

    # not in
    # if "hand" not in alien.keys():
    #     alien["hand"] = 2
    # print(alien["hand"]) # 2

    alien["hand"] = 3
    #.get(self, key, default)
    alien["hand"] = alien.get("hand", 2)
    print(alien["hand"]) #     alien["hand"] = 3   ，     2，     3

    #  key       
    favorite_languages = {
        'jen': 'python',
        'sarah': 'c',
        'edward': 'ruby',
        'phil': 'python',
    }
    for name in sorted(favorite_languages.keys()):
        print(name.title() + ", thank you for taking the poll.")

    #   value
    for value in favorite_languages.values():
        print(value)

    #         ！！！！！！！
    nation = {"china": 200, 'usa': 300, "japan": 100}
    #  key   ，                
    # operator     itemgetter               ，       （               ）
    sortedNation = sorted(nation.items(), key = operator.itemgetter(1))
    print(type(sortedNation))  # 
    print(sortedNation)    # key = operator.itemgetter(1)   [('japan', 100), ('china', 200), ('usa', 300)]
    #print(sortedNation)    # key = operator.itemgetter(0)   [('china', 200), ('japan', 100), ('usa', 300)]
    print(sortedNation[0][0])  # china


def main():
    base_operate()


if __name__ == "__main__":
    main()