import pandas as pd 
df=pd.read_csv('nowcoder.csv')
df['year-month-day']=pd.to_datetime(df['date'],format='%Y-%m-%d').dt.date
# print(df.groupby(['result','year-month-day'])['question_id'].count())  #数值没错，输出格式不对劲
print(df.groupby(['result','year-month-day']).size())