题解 | #牛客网的每日练题量#

import pandas as pd 
df = pd.read_csv('nowcoder.csv',delimiter=',',dtype=object)
df['date'] = pd.to_datetime(df['date'],format='%Y-%m-%d')
dec = df[df['date'].dt.month == 12]
# 获取时间格式中制定的月份
print(dec.groupby('date')['user_id'].count())