import pandas as pd 

df = pd.read_csv('nowcoder.csv')
df.date = pd.to_datetime(df.date).dt.date
array = [df.result.tolist(),df.date.tolist()]
idx = pd.MultiIndex.from_arrays(array,names=['result','year-month-day'])
s = pd.Series(df.question_id.tolist(),index=idx)
print(s.groupby(level=['result','year-month-day']).count())