How to get minimum of each group for each day based on hour criteria

Question

I have given two dataframes below for you to test

df = pd.DataFrame({
    \'subject_id\':[1,1,1,1,1,1,1,1,1,1,1],
    \'time_1\' :[\'2173-04-03 12:35:00\',\'         


        

Answer 1

Try this

from datetime import timedelta

df1['time_1']= pd.to_datetime(df1['time_1'])
df1['date'] = df1['time_1'].dt.date
df1['t_d'] = df1.groupby(['date'])['time_1'].diff().shift(-1)
mask= df1['t_d']>pd.Timedelta(1,'h')
dfa=df1[mask]
dfb=df1[~mask].groupby('date').first().reset_index()
df_f = dfa.merge(dfb, how='outer')
df_f.drop_duplicates(subset='date', keep='first', inplace=True)
df_f.drop(['date','t_d'], axis=1, inplace=True)
df_f.sort_values('time_1')