Set the time of datetime column with condition-CodePudding

I have a dataframe that it has a datetime column 'started_at'

started_at
2019-12-03 10:33:06
2019-12-03 12:29:37
2019-12-03 18:29:37
2019-12-04 11:29:37

I would like to change the time to it, if the time is smaller that a specific time (12:00)

So, the data should become:

started_at
2019-12-03 12:00:00
2019-12-03 12:29:37
2019-12-03 18:29:37
2019-12-04 12:00:00

Any suggestions?

CodePudding user response：

Maybe you can try this

import datetime as dt
for i in range(len(df)):
    fmt = '%Y-%m-%d %H:%M:%S'
    val = dt.datetime.strptime(str(df.loc[i][0]), fmt )
    new_val = dt.datetime.strptime(str(df.loc[i][0]).split(" ")[0]   " 12:00:00", fmt )
    if val < new_val:
        df["started_at"] = df["started_at"].replace(val,new_val)

CodePudding user response：

I would first apply a mask for your times under '12':

mask=df["started_at"].dt.hour<12

Then I would modify the values according to that mask:

df[mask]=df['started_at'].dt.strftime("%Y-%m-%d 12:00:00")