Subtracting hours from a timestamp-CodePudding

I have a data frame with date column as a date time format:

For eg: "2021-02-19T05:00:00 00:00"

I want to subtract some x hours from it. How can it be done?

CodePudding user response：

Let's say you have this timestamp:

time_str = '24/7/2021 11:13:08.230010'

It follows this format:

date_format_str = '%d/%m/%Y %H:%M:%S.%f'

You have to create a datetime object:

given_time = datetime.strptime(time_str, date_format_str)

then you just subtract n. ex n=4

n = 4
final_time = given_time - timedelta(hours=n)

And at then end you return to the initial format

final_time_str = final_time.strftime('%d/%m/%Y %H:%M:%S.%f')

CodePudding user response：

Here you are :

# 1. Import datetime
from datetime import datetime

# 2. Define function
def retrieve_hour(date_str: str, value: int):
    return datetime.datetime.fromisoformat(date_str).hour - value

# Apply to pandas.Dataframe with the value
x = <VALUE>
data[COLUMN_NAME2] = data[COLUMN_NAME1].apply(retrieve_hour, x)

References https://docs.python.org/3.9/library/datetime.html#available-types