I have a dataframe that contains +10K rows, first 4 rows is image below:

[![enter image description here](https://i.stack.imgur.com/bxzH3.png)](https://i.stack.imgur.com/bxzH3.png)

As you can see the hour can be different, and I am trying to replace only hour value to "00" by 'for' loop, but it takes a quiet time. Code is:

```
for i in range(0,len(task_df)):
    task_df["TARGET_END_DATE"].iloc[i]=pd.datetime(year=task_df["TARGET_END_DATE"].iloc[i].year,
                                                month=task_df["TARGET_END_DATE"].iloc[i].month,
                                                day=task_df["TARGET_END_DATE"].iloc[i].day,
                                                hour=0,
                                                minute=0)

```

Is there any quicker way to do it ?