For loops in pandas dataframe, how to filter by days of hourly range and associate a value?-CodePudding

I have a dataframe named df_sub like this:

                   date open    high    low close   volume  
405 2022-01-03 08:00:00 4293.5  4295.5  4291.5  
406 2022-01-03 08:01:00 4294.0  4295.5  4294.0  
407 2022-01-03 08:02:00 4295.5  4297.5  4295.5  
408 2022-01-03 08:03:00 4297.0  4298.0  4296.0  
409 2022-01-03 08:04:00 4296.5  4296.5  4295.0  
... ... ... ... ... ... ... ... ...
5460    2022-01-07 08:55:00 4311.0  4312.0  4310.5  
5461    2022-01-07 08:56:00 4311.5  4311.5  4311.0  
5462    2022-01-07 08:57:00 4311.0  4312.0  4310.0

I need to create a loop of this type:

for row in df_sub:
take a single day (so, in this case 2022-01-03, 04...07) and create a column with df_sub["high"].max() value, 
so i will have the maximum value of the high in all the rows of the same day,
naturally, this implies that in other day the maximum value will be different from the 
previews one because the high will be different.

CodePudding user response：

You can use resample:

df_sub=df_sub.set_index('date')
df_new=df_sub.resample('d')['high'].max()