defaultdict of collections of Python use its advantages

 

user_dict = {}
users = ["baoshan1", "baoshan2", "baoshan3","baoshan1", "baoshan2", "baoshan2"]
for user in users:
    if user not in user_dict:
        user_dict[user] = 1
    else:
        user_dict[user] += 1
print(user_dict)


user_dict =} { 
Users = [ " baoshan1 " , " baoshan2 " , " baoshan3 " , " baoshan1 " , " baoshan2 " , " baoshan2 " ]
 for User in Users: 
    user_dict.setdefault (User, 0) 
    user_dict [User] + =. 1
 Print (user_dict) 


# do not need to do if else the judge 
# efficient, less time user_dict query operations 

from the Collections Import defaultdict 
user_dict= A defaultdict (int) 
Users = [ " baoshan1 " , " baoshan2 " , " baoshan3 " , " baoshan1 " , " baoshan2 " , " baoshan2 " ]
 for User in Users: 
    user_dict [User] + =. 1
 Print (user_dict)
 # a defaultdict benefits transfer callable objects such as int, list, functions, etc.